Christopher Tidy wrote:
Hi folks,

I am looking for a flat screwdriver with an exceptionally thin blade,
for use on clock mechanisms. The blade needs to be at least 3/16" long,
but no more than 25/1000" thick. Does anyone know of a source for such a
screwdriver? UK sources are preferred, if anyone knows of them.

I know I can try grinding my own, but I'm not convinced I can do it neatly.

Follow-ups set to rec.crafts.metalworking.

Many thanks,

Chris Tidy

You're letting your name get to you.

It doesn't have to be tidy, it just has to _work_.

By 3/16" long you mean it fits a 3/16" diameter screw head?

I have a set of "precision screwdrivers" from Radio Shack (US), the
largest one is 9/64" x 0.025 or so. You ought to be able to grind this
freehand on a wheel -- just hold some 3/16" rod straight down to get a
nice radiused cut on each end. I'd be tempted to grind it to a knife
edge, then go straight in until I'd achieved my desired thickness.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

Tim Wescott wrote:
Christopher Tidy wrote:

Hi folks,

I am looking for a flat screwdriver with an exceptionally thin blade,
for use on clock mechanisms. The blade needs to be at least 3/16"
long, but no more than 25/1000" thick. Does anyone know of a source
for such a screwdriver? UK sources are preferred, if anyone knows of
them.

I know I can try grinding my own, but I'm not convinced I can do it
neatly.

Follow-ups set to rec.crafts.metalworking.

Many thanks,

Chris Tidy

You're letting your name get to you.

It doesn't have to be tidy, it just has to _work_.

No, I mean the actual length of the blade is 3/16".

I have a set of "precision screwdrivers" from Radio Shack (US), the
largest one is 9/64" x 0.025 or so. You ought to be able to grind this
freehand on a wheel -- just hold some 3/16" rod straight down to get a
nice radiused cut on each end. I'd be tempted to grind it to a knife
edge, then go straight in until I'd achieved my desired thickness.

I just don't want something which is a bad fit in the slot, and which
may damage the screw heads. That's a good idea to grind it to a knife
edge first. It might help to get a neat shape.

I guess I could try making one from a piece of drill rod, but it might
need quenching, I'm not sure. Or I could just start with a screwdriver.

Chris

Christopher Tidy wrote:
Tim Wescott wrote:
Christopher Tidy wrote:

Hi folks,

I am looking for a flat screwdriver with an exceptionally thin blade,
for use on clock mechanisms. The blade needs to be at least 3/16"
long, but no more than 25/1000" thick. Does anyone know of a source
for such a screwdriver? UK sources are preferred, if anyone knows of
them.

I know I can try grinding my own, but I'm not convinced I can do it
neatly.

Follow-ups set to rec.crafts.metalworking.

Many thanks,

Chris Tidy

You're letting your name get to you.

It doesn't have to be tidy, it just has to _work_.

No, I mean the actual length of the blade is 3/16".

I have a set of "precision screwdrivers" from Radio Shack (US), the
largest one is 9/64" x 0.025 or so. You ought to be able to grind
this freehand on a wheel -- just hold some 3/16" rod straight down to
get a nice radiused cut on each end. I'd be tempted to grind it to a
knife edge, then go straight in until I'd achieved my desired thickness.

I just don't want something which is a bad fit in the slot, and which
may damage the screw heads. That's a good idea to grind it to a knife
edge first. It might help to get a neat shape.

I find it helps a lot to get the thickness even -- wedge shaped
screwdrivers are a pain.

I guess I could try making one from a piece of drill rod, but it might
need quenching, I'm not sure. Or I could just start with a screwdriver.

If I need a one-off screwdriver I often start with music wire from a
hobby shop. If you don't let it get hot it stays pretty hard.

But quenching your own drill rod is undeniably more manly.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

On 2008-10-14, Christopher Tidy wrote:
Tim Wescott wrote:

[ ... ]

It doesn't have to be tidy, it just has to _work_.

No, I mean the actual length of the blade is 3/16".

The length from handle to tip, or the length of the parallel
surfaces to go into the slot in the screw head? 3/16" is awfully short
from handle to tip. 4.76mm total length.

I have a set of "precision screwdrivers" from Radio Shack (US), the
largest one is 9/64" x 0.025 or so. You ought to be able to grind this
freehand on a wheel -- just hold some 3/16" rod straight down to get a
nice radiused cut on each end. I'd be tempted to grind it to a knife
edge, then go straight in until I'd achieved my desired thickness.

Except that this will leave the blade tapered, so it will be
particularly thin at the bottom of the slot, and likely to twist and cam
out of the slot.

I just don't want something which is a bad fit in the slot, and which
may damage the screw heads. That's a good idea to grind it to a knife
edge first. It might help to get a neat shape.

Grind on the top of the wheel (wheel coming towards you),
allowing the wheel surface to produce nearly parallel surfaces at the
tip. Put something soft and large on it (soft wood like pine will do) so
if it digs in from a slight misalignment, it won't have a small end to
be driven into your body.

If you want a non-slip tip, make the final grinding at right
angles to the shank so the grinding marks will act as a gripping
surface.

I guess I could try making one from a piece of drill rod, but it might
need quenching, I'm not sure. Or I could just start with a screwdriver.

Don't get it that hot and quench. This will make it harder,
more brittle, and more likely to break off in the slot. Just grind
gently -- keep it fairly cool, and the default temper of drill rod should
be very good for your purpose.

Note that it is standard practice for gunsmiths to make
individual screwdrivers to precisely fit the screw slots in individual
guns, so it is not difficult to do. And an old clock mechanism sounds
like something which should get similar care -- especially since screw
slots and screwdriver blades were not standardized during the times when
some of these were made.

I've made specialized ones to fit the screw slots on English
made concertinas. I used a Dremel grinding stone in a Unimat lathe to
give a small enough radius for the purpose. I also used an index head
mounted in the cross-slide to allow making the curve on both sides the
same -- take pass with the longitudinal feed, rotate 180 degrees on the
index head, make the same pass on the other side of the blade, then
measure to determine how much to take off on the next pass to precisely
fit the screw slot.

Good Luck,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

I wouldn't grind on a wheel at all, I would start with the nearest oversize
jewellers' screwdriver and grind by hand on a normal "chisel sharpening"
stone. (On the edge, if it is a good one, to avoid making a hollow). Or
these days on one of those diamond plates.

newshound wrote:
I wouldn't grind on a wheel at all, I would start with the nearest oversize
jewellers' screwdriver and grind by hand on a normal "chisel sharpening"
stone. (On the edge, if it is a good one, to avoid making a hollow). Or
these days on one of those diamond plates.

Or even a file.

"Christopher Tidy" wrote in message
...
Cydrome Leader wrote:
newshound wrote:

I wouldn't grind on a wheel at all, I would start with the nearest
oversize jewellers' screwdriver and grind by hand on a normal "chisel
sharpening" stone. (On the edge, if it is a good one, to avoid making a
hollow). Or these days on one of those diamond plates.


Or even a file.

I guess you can file drill rod. I'm not sure you could file a good
screwdriver, though. And poor screwdrivers, in my opinion, are not worth
having.

Chris


The best quality jewellers screwdrivers can be filed! You don't want a blade
that is very hard, just tough. they should be sharpened by filing cross
wise, as the tool marks help the blade "grip" the slot.


Steve R.

DoN. Nichols wrote:
On 2008-10-14, Christopher Tidy wrote:

Tim Wescott wrote:


[ ... ]


It doesn't have to be tidy, it just has to _work_.

No, I mean the actual length of the blade is 3/16".


The length from handle to tip, or the length of the parallel
surfaces to go into the slot in the screw head? 3/16" is awfully short

Sorry, it looks like I've created some confusion. I should probably have
said 3/16" wide, but I wanted to avoid confusion between width and
thickness. I am talking about the tip only.

I have a set of "precision screwdrivers" from Radio Shack (US), the
largest one is 9/64" x 0.025 or so. You ought to be able to grind this
freehand on a wheel -- just hold some 3/16" rod straight down to get a
nice radiused cut on each end. I'd be tempted to grind it to a knife
edge, then go straight in until I'd achieved my desired thickness.


Except that this will leave the blade tapered, so it will be
particularly thin at the bottom of the slot, and likely to twist and cam
out of the slot.

Good point. Unless you can grind away a curved piece of material, so
that the blade faces are parallel at the tip. I think this is what
you're suggesting below.

I just don't want something which is a bad fit in the slot, and which
may damage the screw heads. That's a good idea to grind it to a knife
edge first. It might help to get a neat shape.


Grind on the top of the wheel (wheel coming towards you),
allowing the wheel surface to produce nearly parallel surfaces at the
tip. Put something soft and large on it (soft wood like pine will do) so
if it digs in from a slight misalignment, it won't have a small end to
be driven into your body.

This sounds a bit risky. Something that, going by my gut reaction, I
would prefer not to do. Also, the wheels on the grinder I have access to
are covered at the top. The are only exposed at the front.

If you want a non-slip tip, make the final grinding at right
angles to the shank so the grinding marks will act as a gripping
surface.


I guess I could try making one from a piece of drill rod, but it might
need quenching, I'm not sure. Or I could just start with a screwdriver.


Don't get it that hot and quench. This will make it harder,
more brittle, and more likely to break off in the slot. Just grind
gently -- keep it fairly cool, and the default temper of drill rod should
be very good for your purpose.

Surely drill rod in its raw form isn't as hard wearing as a good
screwdriver, is it?

Note that it is standard practice for gunsmiths to make
individual screwdrivers to precisely fit the screw slots in individual
guns, so it is not difficult to do. And an old clock mechanism sounds
like something which should get similar care -- especially since screw
slots and screwdriver blades were not standardized during the times when
some of these were made.

I was referred to the gun tools supplier Brownells yesterday
(http://www.brownells.com). They have a set of especially thin
screwdriver bits which look suitable. But I e-mailed them and found out
that it's $35 to have them shipped to England. That put me off a bit,
but I might still go for them as I think they'd be useful. Anyone know
how good the Brownells tools are?

Many thanks,

Chris

newshound wrote:
I wouldn't grind on a wheel at all, I would start with the nearest oversize
jewellers' screwdriver and grind by hand on a normal "chisel sharpening"
stone. (On the edge, if it is a good one, to avoid making a hollow). Or
these days on one of those diamond plates.

If the hole is at least 5 mm across, this will possibly do:
https://www.watchtool.co.uk/bergeon-...es-p-6682.html

Does anyone know the difference between the India and Arkansas grinding
stones which are offered with them?

Best wishes,

Chris

Cydrome Leader wrote:
newshound wrote:

I wouldn't grind on a wheel at all, I would start with the nearest oversize
jewellers' screwdriver and grind by hand on a normal "chisel sharpening"
stone. (On the edge, if it is a good one, to avoid making a hollow). Or
these days on one of those diamond plates.


Or even a file.

I guess you can file drill rod. I'm not sure you could file a good
screwdriver, though. And poor screwdrivers, in my opinion, are not worth
having.

Chris

On 2008-10-15, Christopher Tidy wrote:
DoN. Nichols wrote:
On 2008-10-14, Christopher Tidy wrote:

Tim Wescott wrote:


[ ... ]


It doesn't have to be tidy, it just has to _work_.

No, I mean the actual length of the blade is 3/16".


The length from handle to tip, or the length of the parallel
surfaces to go into the slot in the screw head? 3/16" is awfully short

Sorry, it looks like I've created some confusion. I should probably have
said 3/16" wide, but I wanted to avoid confusion between width and
thickness. I am talking about the tip only.

O.K. The words "width" and "thick" should have sufficed.

[ ... ]

Except that this will leave the blade tapered, so it will be
particularly thin at the bottom of the slot, and likely to twist and cam
out of the slot.

Good point. Unless you can grind away a curved piece of material, so
that the blade faces are parallel at the tip. I think this is what
you're suggesting below.

Yes.

I just don't want something which is a bad fit in the slot, and which
may damage the screw heads. That's a good idea to grind it to a knife
edge first. It might help to get a neat shape.


Grind on the top of the wheel (wheel coming towards you),
allowing the wheel surface to produce nearly parallel surfaces at the
tip. Put something soft and large on it (soft wood like pine will do) so
if it digs in from a slight misalignment, it won't have a small end to
be driven into your body.

This sounds a bit risky. Something that, going by my gut reaction, I
would prefer not to do. Also, the wheels on the grinder I have access to
are covered at the top. The are only exposed at the front.

Adjust the rests down out of the way (or just temporarily
remove them) and you can get at the curve on the top front of the
wheels.

If you want a non-slip tip, make the final grinding at right
angles to the shank so the grinding marks will act as a gripping
surface.


I guess I could try making one from a piece of drill rod, but it might
need quenching, I'm not sure. Or I could just start with a screwdriver.


Don't get it that hot and quench. This will make it harder,
more brittle, and more likely to break off in the slot. Just grind
gently -- keep it fairly cool, and the default temper of drill rod should
be very good for your purpose.

Surely drill rod in its raw form isn't as hard wearing as a good
screwdriver, is it?

It is generally a lot tougher than mild steel at least. Heat
and quench and it will be too brittle. And a good screwdriver is not
seriously hardened for the same reason. Cheap ones can be either mild
steel which will never harden, or carbon steel which may be too hardened
and likely to break under serious use. (I've seen both.)

*Seriously* good screwdrivers are likely be forged steel, and
ground to final dimensions.

But if you heat and quench, you will have something too brittle,
and will have to re-heat to draw the temper back to something more
reasonable.

Almost nothing is produced full hard -- tools need to be tough
as well as hard.

Note that it is standard practice for gunsmiths to make
individual screwdrivers to precisely fit the screw slots in individual
guns, so it is not difficult to do. And an old clock mechanism sounds
like something which should get similar care -- especially since screw
slots and screwdriver blades were not standardized during the times when
some of these were made.

I was referred to the gun tools supplier Brownells yesterday
(http://www.brownells.com). They have a set of especially thin
screwdriver bits which look suitable. But I e-mailed them and found out
that it's $35 to have them shipped to England. That put me off a bit,
but I might still go for them as I think they'd be useful. Anyone know
how good the Brownells tools are?

From what I have heard, they are good -- but I have never seen
ones which I knew to be Brownells.

But really -- try making something before you spend all that
money shipping things across the big pond. You will probably discover
that it isn't nearly as difficult as you appear to think it is. And
each one you make will be that much easier than the previous one as you
gain experience.

Good Luck,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

Christopher Tidy wrote:

I was referred to the gun tools supplier Brownells yesterday
(http://www.brownells.com). They have a set of especially thin
screwdriver bits which look suitable. But I e-mailed them and found out
that it's $35 to have them shipped to England. That put me off a bit,
but I might still go for them as I think they'd be useful. Anyone know
how good the Brownells tools are?

Brownells is THE standard for quality gunsmithing tools and supplies.
I can't imagine buying anything from them that is not good quality,
perhaps exceptional quality.

DoN. Nichols wrote:

The length from handle to tip, or the length of the parallel
surfaces to go into the slot in the screw head? 3/16" is awfully short

Sorry, it looks like I've created some confusion. I should probably have
said 3/16" wide, but I wanted to avoid confusion between width and
thickness. I am talking about the tip only.


O.K. The words "width" and "thick" should have sufficed.

I was just thinking that "length" and "width" could not be interpreted
as being the same thing, whereas "width" and "thickness" could be. Never
mind. It didn't work!

Except that this will leave the blade tapered, so it will be
particularly thin at the bottom of the slot, and likely to twist and cam
out of the slot.

Good point. Unless you can grind away a curved piece of material, so
that the blade faces are parallel at the tip. I think this is what
you're suggesting below.


Yes.


I just don't want something which is a bad fit in the slot, and which
may damage the screw heads. That's a good idea to grind it to a knife
edge first. It might help to get a neat shape.


Grind on the top of the wheel (wheel coming towards you),
allowing the wheel surface to produce nearly parallel surfaces at the
tip. Put something soft and large on it (soft wood like pine will do) so
if it digs in from a slight misalignment, it won't have a small end to
be driven into your body.

This sounds a bit risky. Something that, going by my gut reaction, I
would prefer not to do. Also, the wheels on the grinder I have access to
are covered at the top. The are only exposed at the front.


Adjust the rests down out of the way (or just temporarily
remove them) and you can get at the curve on the top front of the
wheels.

You don't think there's a chance that the screwdriver will end up in my
chest, if the tip catches on the wheel?

If you want a non-slip tip, make the final grinding at right
angles to the shank so the grinding marks will act as a gripping
surface.



I guess I could try making one from a piece of drill rod, but it might
need quenching, I'm not sure. Or I could just start with a screwdriver.


Don't get it that hot and quench. This will make it harder,
more brittle, and more likely to break off in the slot. Just grind
gently -- keep it fairly cool, and the default temper of drill rod should
be very good for your purpose.

Surely drill rod in its raw form isn't as hard wearing as a good
screwdriver, is it?


It is generally a lot tougher than mild steel at least. Heat
and quench and it will be too brittle. And a good screwdriver is not
seriously hardened for the same reason. Cheap ones can be either mild
steel which will never harden, or carbon steel which may be too hardened
and likely to break under serious use. (I've seen both.)

I discovered this when I tried to turn and tap drill rod. It was rather
difficult.

*Seriously* good screwdrivers are likely be forged steel, and
ground to final dimensions.

The best screwdrivers I have are a set made by Wera. Nick Mueller
recommended them. They make the other screwdrivers I have look awful by
comparison. The just fit the screw heads so precisely.

But if you heat and quench, you will have something too brittle,
and will have to re-heat to draw the temper back to something more
reasonable.

Almost nothing is produced full hard -- tools need to be tough
as well as hard.


Note that it is standard practice for gunsmiths to make
individual screwdrivers to precisely fit the screw slots in individual
guns, so it is not difficult to do. And an old clock mechanism sounds
like something which should get similar care -- especially since screw
slots and screwdriver blades were not standardized during the times when
some of these were made.

I was referred to the gun tools supplier Brownells yesterday
(http://www.brownells.com). They have a set of especially thin
screwdriver bits which look suitable. But I e-mailed them and found out
that it's $35 to have them shipped to England. That put me off a bit,
but I might still go for them as I think they'd be useful. Anyone know
how good the Brownells tools are?


From what I have heard, they are good -- but I have never seen
ones which I knew to be Brownells.

But really -- try making something before you spend all that
money shipping things across the big pond. You will probably discover
that it isn't nearly as difficult as you appear to think it is. And
each one you make will be that much easier than the previous one as you
gain experience.

I am still thinking about the Brownells set. Having looked at the
articles I want to work on, I figure that I need about six thin
screwdrivers right now. If I buy six good screwdrivers to grind, it will
cost a significant proportion of the cost of the Brownells set, I might
mess them up when grinding, and I'll only have six. If I want to try
making them from drill rod, I'll have to buy some rod (I only have one
suitable size in stock), and I'm not sure how I'd make good handles.

I'm just thinking that making my own might cost a similar amount to the
Brownells set, even though it is expensive.

Many thanks for the advice.

Chris

RB wrote:
Christopher Tidy wrote:

I was referred to the gun tools supplier Brownells yesterday
(http://www.brownells.com). They have a set of especially thin
screwdriver bits which look suitable. But I e-mailed them and found
out that it's $35 to have them shipped to England. That put me off a
bit, but I might still go for them as I think they'd be useful. Anyone
know how good the Brownells tools are?


Brownells is THE standard for quality gunsmithing tools and supplies.
I can't imagine buying anything from them that is not good quality,
perhaps exceptional quality.

I am tempted by the set. I think it would see quite a lot of use. My
only reluctance is that I'd prefer individual screwdrivers to a bit set
and universal handle. A universal handle can be a bit unwieldly with the
smaller sizes of bit, and they aren't always a tight fit. But Brownells
do not seem to offer individual screwdrivers with thin tips.

It's nevertheless something I can't find in Europe. Neither at gun or
clock tool specialists. Guess it must be the strict gun laws here. It's
funny how Brownells note that the thin screw slots are common on
European guns. It's likely that those guns are probably now being used
in the USA.

I'm going to think about it for a week or so. The total cost is a bit
prohibitive, but I may eventually rationalise the purchase.

Best wishes,

Chris

On 2008-10-16, Christopher Tidy wrote:
DoN. Nichols wrote:

[ ... ]

O.K. The words "width" and "thick" should have sufficed.

I was just thinking that "length" and "width" could not be interpreted
as being the same thing, whereas "width" and "thickness" could be. Never
mind. It didn't work!

When you use both words in the same description, it is logical
to assume that they mean different dimensions.

[ ... ]

This sounds a bit risky. Something that, going by my gut reaction, I
would prefer not to do. Also, the wheels on the grinder I have access to
are covered at the top. The are only exposed at the front.


Adjust the rests down out of the way (or just temporarily
remove them) and you can get at the curve on the top front of the
wheels.

You don't think there's a chance that the screwdriver will end up in my
chest, if the tip catches on the wheel?

Not too likely. since you should not get the tip at an angle
which makes that likely. And it is more likely to be driven down than
towards your chest, given the presence of the guard at the top.

But that is why I suggested putting a good handle on it first so
it is too blunt to penetrate your body.

[ ... ]

Surely drill rod in its raw form isn't as hard wearing as a good
screwdriver, is it?


It is generally a lot tougher than mild steel at least. Heat
and quench and it will be too brittle. And a good screwdriver is not
seriously hardened for the same reason. Cheap ones can be either mild
steel which will never harden, or carbon steel which may be too hardened
and likely to break under serious use. (I've seen both.)

I discovered this when I tried to turn and tap drill rod. It was rather
difficult.

Therefore tough enough to be a good screwdriver.

*Seriously* good screwdrivers are likely be forged steel, and
ground to final dimensions.

The best screwdrivers I have are a set made by Wera. Nick Mueller
recommended them. They make the other screwdrivers I have look awful by
comparison. The just fit the screw heads so precisely.

Yes -- with the caveat that all that I have have the tip width
and exposed blade length specified in metric units, which may mean that they are
not a perfect fit for an old imperial screw. I note that the two in my
belt pouch ("Wiha", not "Wera") don't specify the blade thickness. The
2.5x50 (width & length) measures at 0.59mm (probably target of 0.60mm),
or about 0.021".

The older (and larger) ones were made in Germany by Belzer, and
are respectively:
(thickness x width x exposed shank length)

1.0x6x100
0.6x4.5x100

[ ... ]

I was referred to the gun tools supplier Brownells yesterday
(http://www.brownells.com). They have a set of especially thin
screwdriver bits which look suitable. But I e-mailed them and found out
that it's $35 to have them shipped to England. That put me off a bit,
but I might still go for them as I think they'd be useful. Anyone know
how good the Brownells tools are?


From what I have heard, they are good -- but I have never seen
ones which I knew to be Brownells.

But really -- try making something before you spend all that
money shipping things across the big pond. You will probably discover
that it isn't nearly as difficult as you appear to think it is. And
each one you make will be that much easier than the previous one as you
gain experience.

I am still thinking about the Brownells set. Having looked at the
articles I want to work on, I figure that I need about six thin
screwdrivers right now. If I buy six good screwdrivers to grind, it will
cost a significant proportion of the cost of the Brownells set, I might
mess them up when grinding, and I'll only have six. If I want to try
making them from drill rod, I'll have to buy some rod (I only have one
suitable size in stock), and I'm not sure how I'd make good handles.

You have a lathe? You have a knurling tool? Turn a handle from
aluminum or brass, knurl it for a good grip, drill to fit the shank,
drill for a setscrew, and mill (or file) a flat on the shank for the
setscrew to bear upon. Do this *before* you grind the tip, so you have
something to blunt the shank if it does happen to dig in -- though it
shouldn't as long as you are holding the tip tangent to the wheel. And
you really don't want to be pressing hard enough to encourage a dig-in
even at a wrong angle. Keep the pressure light, so you don't overheat
the workpiece.

I'm just thinking that making my own might cost a similar amount to the
Brownells set, even though it is expensive.

It would be a good set to have -- but you really should be able
to make your own, too. I made my first one back in about 1977 I think,
using a Unimat SL-1000 for the grinding, and an old worn-out
Atlas/Craftsman 6x18" lathe for the turning and knurling.

I used a fairly small mounted stone to keep the tip length
short before it got thicker and stronger.

Good Luck,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

DoN. Nichols wrote:

This sounds a bit risky. Something that, going by my gut reaction, I
would prefer not to do. Also, the wheels on the grinder I have access to
are covered at the top. The are only exposed at the front.


Adjust the rests down out of the way (or just temporarily
remove them) and you can get at the curve on the top front of the
wheels.

You don't think there's a chance that the screwdriver will end up in my
chest, if the tip catches on the wheel?


Not too likely. since you should not get the tip at an angle
which makes that likely. And it is more likely to be driven down than
towards your chest, given the presence of the guard at the top.

I had a look at the grinder yesterday. I think it would be possible to
get a screwdriver bit into the right position, and that it probably
wouldn't stick in the wheel. But then I had a look for a screwdriver of
the right size to grind, and could only find my light-up electrical
screwdriver. I didn't want to modify that, so I'll have to wait until
I'm in a tool shop to buy a suitable screwdriver.

I think perhaps part of my reluctance is because I'm a bit of a
perfectionist. I like good, accurate tools and I'm not sure that I can
make a screwdriver of that standard. Good screwdrivers are really nice
to use. The way they snugly fit screw heads is satisfying.

The best screwdrivers I have are a set made by Wera. Nick Mueller
recommended them. They make the other screwdrivers I have look awful by
comparison. The just fit the screw heads so precisely.


Yes -- with the caveat that all that I have have the tip width
and exposed blade length specified in metric units, which may mean that they are
not a perfect fit for an old imperial screw. I note that the two in my
belt pouch ("Wiha", not "Wera") don't specify the blade thickness. The
2.5x50 (width & length) measures at 0.59mm (probably target of 0.60mm),
or about 0.021".

Wera and Wiha are different brands. Wera screwdrivers have a distinctive
multicoloured handle with the dimensions of the tip printed on it. I've
been very impressed with them.

The Wera screwdrivers also have a hexagonal shaft. It occurred to me
yesterday that this could be helpful when trying to modify one, as it
would help to ensure that the two ground faces are parallel.

The older (and larger) ones were made in Germany by Belzer, and
are respectively:
(thickness x width x exposed shank length)

1.0x6x100
0.6x4.5x100

[ ... ]


I was referred to the gun tools supplier Brownells yesterday
(http://www.brownells.com). They have a set of especially thin
screwdriver bits which look suitable. But I e-mailed them and found out
that it's $35 to have them shipped to England. That put me off a bit,
but I might still go for them as I think they'd be useful. Anyone know
how good the Brownells tools are?


From what I have heard, they are good -- but I have never seen
ones which I knew to be Brownells.

But really -- try making something before you spend all that
money shipping things across the big pond. You will probably discover
that it isn't nearly as difficult as you appear to think it is. And
each one you make will be that much easier than the previous one as you
gain experience.

I am still thinking about the Brownells set. Having looked at the
articles I want to work on, I figure that I need about six thin
screwdrivers right now. If I buy six good screwdrivers to grind, it will
cost a significant proportion of the cost of the Brownells set, I might
mess them up when grinding, and I'll only have six. If I want to try
making them from drill rod, I'll have to buy some rod (I only have one
suitable size in stock), and I'm not sure how I'd make good handles.


You have a lathe? You have a knurling tool? Turn a handle from
aluminum or brass, knurl it for a good grip, drill to fit the shank,
drill for a setscrew, and mill (or file) a flat on the shank for the
setscrew to bear upon. Do this *before* you grind the tip, so you have
something to blunt the shank if it does happen to dig in -- though it
shouldn't as long as you are holding the tip tangent to the wheel. And
you really don't want to be pressing hard enough to encourage a dig-in
even at a wrong angle. Keep the pressure light, so you don't overheat
the workpiece.

I've got access to my father's lathe, but not a knurling tool.

I'm just thinking that making my own might cost a similar amount to the
Brownells set, even though it is expensive.


It would be a good set to have -- but you really should be able
to make your own, too. I made my first one back in about 1977 I think,
using a Unimat SL-1000 for the grinding, and an old worn-out
Atlas/Craftsman 6x18" lathe for the turning and knurling.

I think the Brownells set is likely out of the question because of their
ludicrous shipping charges. I am going to call a few horological
suppliers on Monday see if they know of a source. Surely someone must
make suitable screwdrivers?

If I don't have any success, I will have to make one and see how neat it
turns out.

Many thanks,

Chris

On Sat, 18 Oct 2008 13:46:37 +0000, Christopher Tidy
wrote:

snip
I think perhaps part of my reluctance is because I'm a bit of a
perfectionist. I like good, accurate tools and I'm not sure that I can
make a screwdriver of that standard. Good screwdrivers are really nice
to use. The way they snugly fit screw heads is satisfying.

Somebody else (most likely several) mentioned it already,
but try using small hex keys (Allen wrenches). They are
relatively inexpensive, hard and tough. If you grind/cut the
90 degree turn out of them a nice Pin Vice will hold them as
a handle. Being hex shaped they shouldn't slip in the Pin
Vice.

Don't worry about perfection, make something that will work
and get the job done. That will be satisfying enough

--
Leon Fisk
Grand Rapids MI/Zone 5b
Remove no.spam for email

On 2008-10-18, Christopher Tidy wrote:
DoN. Nichols wrote:

[ ... ]

You don't think there's a chance that the screwdriver will end up in my
chest, if the tip catches on the wheel?


Not too likely. since you should not get the tip at an angle
which makes that likely. And it is more likely to be driven down than
towards your chest, given the presence of the guard at the top.

I had a look at the grinder yesterday. I think it would be possible to
get a screwdriver bit into the right position, and that it probably
wouldn't stick in the wheel. But then I had a look for a screwdriver of
the right size to grind, and could only find my light-up electrical
screwdriver. I didn't want to modify that, so I'll have to wait until
I'm in a tool shop to buy a suitable screwdriver.

I would really not want to modify a good screwdriver -- I would
prefer to start from scratch. A cheap screwdriver I would (and have)
modified -- for example when I needed a split blade to drive a nut which
had a slot on either side of the screw -- but needed a gap in the blade
for the screw to project into. (Hex head on the screw, so the nut
*must* rotate, and the nut fit into a recess in a connector.) So I just
grabbed a cheap screwdriver (Stubby one of the kind provided in Army
toolkits, since I was working for an Army R&D lab at the time, and this
was truly a government project, so I could expend a screwdriver for the
cause. I simply took a file to cut the needed notch.

Perhaps what you need to do is to get a screwdriver with
interchangeable tips (here they have 1/4" hex shanks and a corresponding
socket in the handle), where you can buy a large number of hex
screwdriver bits of many sizes and styles, and simply grind the bit to
fit a particular screw -- mark it, and keep it for the next time you
need that size. Replacement bits are inexpensive, are good tool steel
for the purpose, and it should be easy to make a fixture to hold the
1/4" hex shank while grinding it.

I think perhaps part of my reluctance is because I'm a bit of a
perfectionist. I like good, accurate tools and I'm not sure that I can
make a screwdriver of that standard. Good screwdrivers are really nice
to use. The way they snugly fit screw heads is satisfying.

Good screwdrivers with replaceable bits sounds the way to go,
then.

But a cheap screwdriver which has been reground to fit the screw
in question is better than a perfect screwdriver with is either too
thick or too thin.

The best screwdrivers I have are a set made by Wera. Nick Mueller
recommended them. They make the other screwdrivers I have look awful by
comparison. The just fit the screw heads so precisely.


Yes -- with the caveat that all that I have have the tip width
and exposed blade length specified in metric units, which may mean that they are
not a perfect fit for an old imperial screw. I note that the two in my
belt pouch ("Wiha", not "Wera") don't specify the blade thickness. The
2.5x50 (width & length) measures at 0.59mm (probably target of 0.60mm),
or about 0.021".

Wera and Wiha are different brands. Wera screwdrivers have a distinctive
multicoloured handle with the dimensions of the tip printed on it. I've
been very impressed with them.

That sounds like a description of the Wiha ones in my belt
pouch. Handles are black with a red cap which pivots to allow you to
hold it pressed into the screw slot with a single fingertip. The
width and thickness are printed on the black part of the handle.

The Wera screwdrivers also have a hexagonal shaft. It occurred to me
yesterday that this could be helpful when trying to modify one, as it
would help to ensure that the two ground faces are parallel.

Hmm ... I've seen some screwdrivers (SnapOn among them) which
have a hex forged just below the handle for allowing wrench to assist
with a really tight screw. (And yes, the screwdriver was forged tough
enough to handle that kind of abuse.)

[ ... ]

You have a lathe? You have a knurling tool? Turn a handle from
aluminum or brass, knurl it for a good grip, drill to fit the shank,
drill for a setscrew, and mill (or file) a flat on the shank for the
setscrew to bear upon. Do this *before* you grind the tip, so you have
something to blunt the shank if it does happen to dig in -- though it
shouldn't as long as you are holding the tip tangent to the wheel. And
you really don't want to be pressing hard enough to encourage a dig-in
even at a wrong angle. Keep the pressure light, so you don't overheat
the workpiece.

I've got access to my father's lathe, but not a knurling tool.

Then consider getting a knurling tool for it. Ideally a
scissors style knurling tool, so you don't overstress the machine.

[ ... ]

I think the Brownells set is likely out of the question because of their
ludicrous shipping charges. I am going to call a few horological
suppliers on Monday see if they know of a source. Surely someone must
make suitable screwdrivers?

Changeable tip screwdrivers, with lots of spare tips so you can
grind them to fit different screws.

If I don't have any success, I will have to make one and see how neat it
turns out.

Good Luck,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

On 19 Oct 2008 00:53:49 GMT, "DoN. Nichols"
wrote:


Perhaps what you need to do is to get a screwdriver with
interchangeable tips (here they have 1/4" hex shanks


The best are Chapman screwdriver kits


Whenever a Liberal utters the term "Common Sense approach"....grab your
wallet, your ass, and your guns because the sombitch is about to do
something damned nasty to all three of them.

"Christopher Tidy" wrote in message
...
DoN. Nichols wrote:

I would really not want to modify a good screwdriver -- I would
prefer to start from scratch. A cheap screwdriver I would (and have)
modified -- for example when I needed a split blade to drive a nut which
had a slot on either side of the screw -- but needed a gap in the blade
for the screw to project into. (Hex head on the screw, so the nut
*must* rotate, and the nut fit into a recess in a connector.) So I just
grabbed a cheap screwdriver (Stubby one of the kind provided in Army
toolkits, since I was working for an Army R&D lab at the time, and this
was truly a government project, so I could expend a screwdriver for the
cause. I simply took a file to cut the needed notch.

The problem I find with cheap screwdrivers is that they wear quickly, and
sometimes the tip becomes twisted. I have a cheap Stanley flat screwdriver
I bought a while back (it was not one of their most expensive ones) and
the blade distorted in normal use. If I'm going to spend time carefully
modifying a screwdriver, I don't want to find that it rapidly becomes
unusable because of the quality of the material. My experience has been
that cheap screwdrivers are mostly a nuisance.

When I have a soft, cheap one that I want to keep for some reason, I polish
off any plating near the tip and give it two or three passes in
case-hardening compound. This is one situation where you *do* want to temper
after case-hardening, but I just do it with a torch, and temper by color.

--
Ed Huntress

DoN. Nichols wrote:

I would really not want to modify a good screwdriver -- I would
prefer to start from scratch. A cheap screwdriver I would (and have)
modified -- for example when I needed a split blade to drive a nut which
had a slot on either side of the screw -- but needed a gap in the blade
for the screw to project into. (Hex head on the screw, so the nut
*must* rotate, and the nut fit into a recess in a connector.) So I just
grabbed a cheap screwdriver (Stubby one of the kind provided in Army
toolkits, since I was working for an Army R&D lab at the time, and this
was truly a government project, so I could expend a screwdriver for the
cause. I simply took a file to cut the needed notch.

The problem I find with cheap screwdrivers is that they wear quickly,
and sometimes the tip becomes twisted. I have a cheap Stanley flat
screwdriver I bought a while back (it was not one of their most
expensive ones) and the blade distorted in normal use. If I'm going to
spend time carefully modifying a screwdriver, I don't want to find that
it rapidly becomes unusable because of the quality of the material. My
experience has been that cheap screwdrivers are mostly a nuisance.

Perhaps what you need to do is to get a screwdriver with
interchangeable tips (here they have 1/4" hex shanks and a corresponding
socket in the handle), where you can buy a large number of hex
screwdriver bits of many sizes and styles, and simply grind the bit to
fit a particular screw -- mark it, and keep it for the next time you
need that size. Replacement bits are inexpensive, are good tool steel
for the purpose, and it should be easy to make a fixture to hold the
1/4" hex shank while grinding it.

This did occur to me. It also occurred to me that if I could get 1/4"
hexagonal drill rod, this would allow me to make screwdriver bits
without needing to make a handle. But I couldn't find any.

I think perhaps part of my reluctance is because I'm a bit of a
perfectionist. I like good, accurate tools and I'm not sure that I can
make a screwdriver of that standard. Good screwdrivers are really nice
to use. The way they snugly fit screw heads is satisfying.


Good screwdrivers with replaceable bits sounds the way to go,
then.

I think in this case you're right. I do have a preference for fixed
blade screwdrivers when they're available, though. Interchangeable bits
aren't always held tightly in the handle, and the handle is usually a
bit bulkier.

I had wondered about buying interchangeable bits and attempting to
modify them using a half round file, but I'm not sure if they could
readily be filed.

But a cheap screwdriver which has been reground to fit the screw
in question is better than a perfect screwdriver with is either too
thick or too thin.

True enough. I wish the makers of the best screwdrivers would make a
wider range of tip sizes.

The best screwdrivers I have are a set made by Wera. Nick Mueller
recommended them. They make the other screwdrivers I have look awful by
comparison. The just fit the screw heads so precisely.


Yes -- with the caveat that all that I have have the tip width
and exposed blade length specified in metric units, which may mean that they are
not a perfect fit for an old imperial screw. I note that the two in my
belt pouch ("Wiha", not "Wera") don't specify the blade thickness. The
2.5x50 (width & length) measures at 0.59mm (probably target of 0.60mm),
or about 0.021".

Wera and Wiha are different brands. Wera screwdrivers have a distinctive
multicoloured handle with the dimensions of the tip printed on it. I've
been very impressed with them.


That sounds like a description of the Wiha ones in my belt
pouch. Handles are black with a red cap which pivots to allow you to
hold it pressed into the screw slot with a single fingertip. The
width and thickness are printed on the black part of the handle.

These are the ones I have:
http://www.screwfix.com/sfd/i/cat/31/p2613331_l.jpg

The Wera screwdrivers also have a hexagonal shaft. It occurred to me
yesterday that this could be helpful when trying to modify one, as it
would help to ensure that the two ground faces are parallel.


Hmm ... I've seen some screwdrivers (SnapOn among them) which
have a hex forged just below the handle for allowing wrench to assist
with a really tight screw. (And yes, the screwdriver was forged tough
enough to handle that kind of abuse.)

Yes, they have a larger hexagonal section below the handle for this
purpose in addition to the hexagonal shaft. Also, the shaft goes right
the way through the plastic handle and emerges as a metal cap.

I've got access to my father's lathe, but not a knurling tool.


Then consider getting a knurling tool for it. Ideally a
scissors style knurling tool, so you don't overstress the machine.

I just had a look at knurling tools. Good ones are relatively expensive.
A good one looks to be a similar price to that Brownells screwdriver
set, even including the postage.

I think I am coming round to the idea of the Brownells set. It would get
a lot of use. They don't say much about the type of steel they're made
from, though. Some, but not all, screwdrivers advertise "Cr-V" or "Cr-V-Mo".

Best wishes,

Chris

Gunner Asch wrote:
On 19 Oct 2008 00:53:49 GMT, "DoN. Nichols"
wrote:


Perhaps what you need to do is to get a screwdriver with
interchangeable tips (here they have 1/4" hex shanks



The best are Chapman screwdriver kits

Thanks, Gunner. I will have a look to see if they sell especially thin
tipped screwdrivers.

Best wishes,

Chris

On Sun, 19 Oct 2008 13:53:02 +0000, Christopher Tidy
wrote:

Gunner Asch wrote:
On 19 Oct 2008 00:53:49 GMT, "DoN. Nichols"
wrote:


Perhaps what you need to do is to get a screwdriver with
interchangeable tips (here they have 1/4" hex shanks



The best are Chapman screwdriver kits

Thanks, Gunner. I will have a look to see if they sell especially thin
tipped screwdrivers.

Best wishes,

Chris


Chris..they sell ALL sizes of screwdriver bits. Some hair thin.

I use Chapmans exclusivly for working on firearms. Some of the very
old arms use hair thin slots in their screws, and one doesnt want a
screwdriver slipping and scratching the finish.


Gunner

Whenever a Liberal utters the term "Common Sense approach"....grab your
wallet, your ass, and your guns because the sombitch is about to do
something damned nasty to all three of them.

You might find it easier to grind the blade thin on a sanding drum or
the roller of a belt sander. They will give you a hollow grind of
smaller radius than a bench grinding wheel.

Ed Huntress wrote:
"Christopher Tidy" wrote in message
...

DoN. Nichols wrote:


I would really not want to modify a good screwdriver -- I would
prefer to start from scratch. A cheap screwdriver I would (and have)
modified -- for example when I needed a split blade to drive a nut which
had a slot on either side of the screw -- but needed a gap in the blade
for the screw to project into. (Hex head on the screw, so the nut
*must* rotate, and the nut fit into a recess in a connector.) So I just
grabbed a cheap screwdriver (Stubby one of the kind provided in Army
toolkits, since I was working for an Army R&D lab at the time, and this
was truly a government project, so I could expend a screwdriver for the
cause. I simply took a file to cut the needed notch.

The problem I find with cheap screwdrivers is that they wear quickly, and
sometimes the tip becomes twisted. I have a cheap Stanley flat screwdriver
I bought a while back (it was not one of their most expensive ones) and
the blade distorted in normal use. If I'm going to spend time carefully
modifying a screwdriver, I don't want to find that it rapidly becomes
unusable because of the quality of the material. My experience has been
that cheap screwdrivers are mostly a nuisance.


When I have a soft, cheap one that I want to keep for some reason, I polish
off any plating near the tip and give it two or three passes in
case-hardening compound. This is one situation where you *do* want to temper
after case-hardening, but I just do it with a torch, and temper by color.

Handy if you have the compound already, but if not it'll probably cost
you more than a decent screwdriver :-).

Chris

Jim Wilkins wrote:
You might find it easier to grind the blade thin on a sanding drum or
the roller of a belt sander. They will give you a hollow grind of
smaller radius than a bench grinding wheel.

Bergeon make a machine just like that for sharpening screwdrivers. Looks
great, but there's no way I can afford it.

I don't have a motorised sander as I don't do much woodwork.

Best wishes,

Chris

"Christopher Tidy" wrote in message
...
Ed Huntress wrote:
"Christopher Tidy" wrote in message
...

DoN. Nichols wrote:


I would really not want to modify a good screwdriver -- I would
prefer to start from scratch. A cheap screwdriver I would (and have)
modified -- for example when I needed a split blade to drive a nut which
had a slot on either side of the screw -- but needed a gap in the blade
for the screw to project into. (Hex head on the screw, so the nut
*must* rotate, and the nut fit into a recess in a connector.) So I just
grabbed a cheap screwdriver (Stubby one of the kind provided in Army
toolkits, since I was working for an Army R&D lab at the time, and this
was truly a government project, so I could expend a screwdriver for the
cause. I simply took a file to cut the needed notch.

The problem I find with cheap screwdrivers is that they wear quickly, and
sometimes the tip becomes twisted. I have a cheap Stanley flat
screwdriver I bought a while back (it was not one of their most expensive
ones) and the blade distorted in normal use. If I'm going to spend time
carefully modifying a screwdriver, I don't want to find that it rapidly
becomes unusable because of the quality of the material. My experience
has been that cheap screwdrivers are mostly a nuisance.


When I have a soft, cheap one that I want to keep for some reason, I
polish off any plating near the tip and give it two or three passes in
case-hardening compound. This is one situation where you *do* want to
temper after case-hardening, but I just do it with a torch, and temper by
color.

Handy if you have the compound already, but if not it'll probably cost you
more than a decent screwdriver :-).

Right. But any metalworking shop should have some Casenit on hand. I use it
frequently for all sorts of things. Lately I've made some custom hole saws
with it, for trepanning wood on the butt end of a fly rod.

I've heard that those commercial case-hardening compounds are not allowed
for sale in the UK. Is that correct?

--
Ed Huntress

Ed Huntress wrote:

Right. But any metalworking shop should have some Casenit on hand. I use it
frequently for all sorts of things. Lately I've made some custom hole saws
with it, for trepanning wood on the butt end of a fly rod.

I've heard that those commercial case-hardening compounds are not allowed
for sale in the UK. Is that correct?

You can certainly get case hardening compounds here. Whether they are
the same as the ones you can get, I don't know.

But search hard enough and you can get pretty much anything :-).

Chris

On 2008-10-19, Christopher Tidy wrote:
DoN. Nichols wrote:

I would really not want to modify a good screwdriver -- I would
prefer to start from scratch. A cheap screwdriver I would (and have)
modified -- for example when I needed a split blade to drive a nut which
had a slot on either side of the screw -- but needed a gap in the blade
for the screw to project into. (Hex head on the screw, so the nut
*must* rotate, and the nut fit into a recess in a connector.) So I just
grabbed a cheap screwdriver (Stubby one of the kind provided in Army
toolkits, since I was working for an Army R&D lab at the time, and this
was truly a government project, so I could expend a screwdriver for the
cause. I simply took a file to cut the needed notch.

The problem I find with cheap screwdrivers is that they wear quickly,
and sometimes the tip becomes twisted.

Of course -- but a cheap screwdriver to modify to make a
one-time use screwdriver is often quite sufficient.

I have a cheap Stanley flat
screwdriver I bought a while back (it was not one of their most
expensive ones) and the blade distorted in normal use. If I'm going to
spend time carefully modifying a screwdriver, I don't want to find that
it rapidly becomes unusable because of the quality of the material. My
experience has been that cheap screwdrivers are mostly a nuisance.

*One-time* use. If you expect to use it a lot, you start with
good materials.

Perhaps what you need to do is to get a screwdriver with
interchangeable tips (here they have 1/4" hex shanks and a corresponding
socket in the handle), where you can buy a large number of hex
screwdriver bits of many sizes and styles, and simply grind the bit to
fit a particular screw -- mark it, and keep it for the next time you
need that size. Replacement bits are inexpensive, are good tool steel
for the purpose, and it should be easy to make a fixture to hold the
1/4" hex shank while grinding it.

This did occur to me. It also occurred to me that if I could get 1/4"
hexagonal drill rod, this would allow me to make screwdriver bits
without needing to make a handle. But I couldn't find any.

Sure you can. Someone else already posted the source. Allen
keys (1/4" size, obviously). Cut off the elbow, and you have a short
piece and a longer piece. And they are normally good steel. You can
also buy a single size in boxes of 100 or 144 (depending on the size)
for a quite affordable price.

In the MSC catalog, for example, I find:

================================================== ====================
Hex & Torx Keys, Drivers, & Sets Tool Type: Hex End Key Fastener Type:
Standard Hex Measurement Type: Inch Handle Type: L-Key Short Arm Hex
Size: 1/4 Material: Alloy Steel
================================================== ====================

And the price for a box of 100 made by Eklind is $45.28 (Probably about
22 UKP these days.)

The same general description, but

Import $31.16
Allen $57.45
Bondhus $42.32

I think perhaps part of my reluctance is because I'm a bit of a
perfectionist. I like good, accurate tools and I'm not sure that I can
make a screwdriver of that standard. Good screwdrivers are really nice
to use. The way they snugly fit screw heads is satisfying.


Good screwdrivers with replaceable bits sounds the way to go,
then.

I think in this case you're right. I do have a preference for fixed
blade screwdrivers when they're available, though. Interchangeable bits
aren't always held tightly in the handle, and the handle is usually a
bit bulkier.

But -- the interchangeable bits allow me to use them in a
electric screwdriver with adjustable torque limit. For some things, a
manual screwdriver is about as good, but when dealing with (for example)
changing out a set of cards in an old Sun 4/370 computer (3U VME bus),
you have two Allen head screws, M3x0.45 with about 1" of thread to back
out for each card -- and about 12 cards total in the system. And you
can get sets of hex shank screwdriver bits with all kinds of special
security tips as well as the standard slotted, Phillips, Allen and Torx.
Examples are the Offset Phillips (standard four blades, but offset from
the center so they tighten more firmly, and so they intentionally walk
out when you try to remove the screw, Tri-Wing (same as above, but only
three blades), Security Allen (hole in the center of the bit to clear a
pin in the screw head), Security Torx (similar to the Allen),
split-point straight blades, and various other weird types -- all with
1/4" shanks, so they can fit either the manual screwdriver handles or
the electric driver (which has the added benefit of an adjustable torque
limit so you won't strip out screws in mild stamped steel).

The electric screwdriver which I use was originally made by AEG,
and more recently Panasonic and Milwaukee -- same screwdriver, different
color plastic. :-)

I had wondered about buying interchangeable bits and attempting to
modify them using a half round file, but I'm not sure if they could
readily be filed.

If not, they can be ground.

But a cheap screwdriver which has been reground to fit the screw
in question is better than a perfect screwdriver with is either too
thick or too thin.

True enough. I wish the makers of the best screwdrivers would make a
wider range of tip sizes.

I think that the makers of the best screwdrivers are targeting
screws with the proper thickness slot for the width of the blade. The
torque required is defined by the diameter and thread pitch. This
defines the size of the head, and this the width and thickness of the
slot to have sufficient strength to handle these without bending.

Your narrow slotted screws are not really properly designed.
They were made with the size of slotting saw which the maker had on
hand -- and he did not want to buy a bunch of other thicknesses.

[ ... ]

Wera and Wiha are different brands. Wera screwdrivers have a distinctive
multicoloured handle with the dimensions of the tip printed on it. I've
been very impressed with them.


That sounds like a description of the Wiha ones in my belt
pouch. Handles are black with a red cap which pivots to allow you to
hold it pressed into the screw slot with a single fingertip. The
width and thickness are printed on the black part of the handle.

These are the ones I have:
http://www.screwfix.com/sfd/i/cat/31/p2613331_l.jpg

O.K. *Quite* colorful, and too large to fit my belt pouch
(which has my checkbook, several sizes of small screwdrivers, pens,
calculators, and usually a small pin vise all there on my belt).

The Wera screwdrivers also have a hexagonal shaft. It occurred to me
yesterday that this could be helpful when trying to modify one, as it
would help to ensure that the two ground faces are parallel.


Hmm ... I've seen some screwdrivers (SnapOn among them) which
have a hex forged just below the handle for allowing wrench to assist
with a really tight screw. (And yes, the screwdriver was forged tough
enough to handle that kind of abuse.)

Yes, they have a larger hexagonal section below the handle for this
purpose in addition to the hexagonal shaft. Also, the shaft goes right
the way through the plastic handle and emerges as a metal cap.

Hmm ... that latter feature is a design to survive abuse by
hammering on the end of the driver.

I've got access to my father's lathe, but not a knurling tool.


Then consider getting a knurling tool for it. Ideally a
scissors style knurling tool, so you don't overstress the machine.

I just had a look at knurling tools. Good ones are relatively expensive.
A good one looks to be a similar price to that Brownells screwdriver
set, even including the postage.

Yes -- but you can then be equipped to make other tools using
it.

I think I am coming round to the idea of the Brownells set. It would get
a lot of use. They don't say much about the type of steel they're made
from, though. Some, but not all, screwdrivers advertise "Cr-V" or "Cr-V-Mo".

And some which advertise that are still poorly hardened and
tempered -- either too soft, or too brittle.

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

Christopher Tidy wrote in
:

Jim Wilkins wrote:
You might find it easier to grind the blade thin on a sanding drum or
the roller of a belt sander. They will give you a hollow grind of
smaller radius than a bench grinding wheel.

Bergeon make a machine just like that for sharpening screwdrivers. Looks
great, but there's no way I can afford it.

I don't have a motorised sander as I don't do much woodwork.

Best wishes,

Chris



So get a small sanding drum [the type with a 1/4" shank] that you can chuck
into your drill press.

They're cheap.

DoN. Nichols wrote:

The problem I find with cheap screwdrivers is that they wear quickly,
and sometimes the tip becomes twisted.


Of course -- but a cheap screwdriver to modify to make a
one-time use screwdriver is often quite sufficient.

I do expect a set of thin screwdrivers to see a considerable amount of use.

I have a cheap Stanley flat
screwdriver I bought a while back (it was not one of their most
expensive ones) and the blade distorted in normal use. If I'm going to
spend time carefully modifying a screwdriver, I don't want to find that
it rapidly becomes unusable because of the quality of the material. My
experience has been that cheap screwdrivers are mostly a nuisance.


*One-time* use. If you expect to use it a lot, you start with
good materials.

This is why I was thinking of starting with a good quality screwdriver.
I would hate to grind one to exactly the right size, then find it only
lasted a short time.

Perhaps what you need to do is to get a screwdriver with
interchangeable tips (here they have 1/4" hex shanks and a corresponding
socket in the handle), where you can buy a large number of hex
screwdriver bits of many sizes and styles, and simply grind the bit to
fit a particular screw -- mark it, and keep it for the next time you
need that size. Replacement bits are inexpensive, are good tool steel
for the purpose, and it should be easy to make a fixture to hold the
1/4" hex shank while grinding it.

This did occur to me. It also occurred to me that if I could get 1/4"
hexagonal drill rod, this would allow me to make screwdriver bits
without needing to make a handle. But I couldn't find any.


Sure you can. Someone else already posted the source. Allen
keys (1/4" size, obviously). Cut off the elbow, and you have a short
piece and a longer piece. And they are normally good steel. You can
also buy a single size in boxes of 100 or 144 (depending on the size)
for a quite affordable price.

In the MSC catalog, for example, I find:

================================================== ====================
Hex & Torx Keys, Drivers, & Sets Tool Type: Hex End Key Fastener Type:
Standard Hex Measurement Type: Inch Handle Type: L-Key Short Arm Hex
Size: 1/4 Material: Alloy Steel
================================================== ====================

And the price for a box of 100 made by Eklind is $45.28 (Probably about
22 UKP these days.)

The same general description, but

Import $31.16
Allen $57.45
Bondhus $42.32

Allen keys are a useful source, and one I hadn't thought of. Thanks for
that idea. But a box of 100 is about the same price as that thin bit set
from Brownells. Due to the unknown amount of time and experimentation it
will take me to make a good screwdriver bit, I am drawn towards the
Brownells set.

I think perhaps part of my reluctance is because I'm a bit of a
perfectionist. I like good, accurate tools and I'm not sure that I can
make a screwdriver of that standard. Good screwdrivers are really nice
to use. The way they snugly fit screw heads is satisfying.


Good screwdrivers with replaceable bits sounds the way to go,
then.

I think in this case you're right. I do have a preference for fixed
blade screwdrivers when they're available, though. Interchangeable bits
aren't always held tightly in the handle, and the handle is usually a
bit bulkier.


But -- the interchangeable bits allow me to use them in a
electric screwdriver with adjustable torque limit. For some things, a
manual screwdriver is about as good, but when dealing with (for example)
changing out a set of cards in an old Sun 4/370 computer (3U VME bus),
you have two Allen head screws, M3x0.45 with about 1" of thread to back
out for each card -- and about 12 cards total in the system. And you
can get sets of hex shank screwdriver bits with all kinds of special
security tips as well as the standard slotted, Phillips, Allen and Torx.
Examples are the Offset Phillips (standard four blades, but offset from
the center so they tighten more firmly, and so they intentionally walk
out when you try to remove the screw, Tri-Wing (same as above, but only
three blades), Security Allen (hole in the center of the bit to clear a
pin in the screw head), Security Torx (similar to the Allen),
split-point straight blades, and various other weird types -- all with
1/4" shanks, so they can fit either the manual screwdriver handles or
the electric driver (which has the added benefit of an adjustable torque
limit so you won't strip out screws in mild stamped steel).

The electric screwdriver which I use was originally made by AEG,
and more recently Panasonic and Milwaukee -- same screwdriver, different
color plastic. :-)

I have a thing against electric screwdrivers. While they may be faster
and have an adjustable torque limit on some models, I find they give
poor control with slotted screws. I just prefer to use a normal
screwdriver and estimate the required torque. I have only once damaged a
thread in this way, and that was a long time ago, so I don't think I'm
doing too badly.

I had wondered about buying interchangeable bits and attempting to
modify them using a half round file, but I'm not sure if they could
readily be filed.


If not, they can be ground.


But a cheap screwdriver which has been reground to fit the screw
in question is better than a perfect screwdriver with is either too
thick or too thin.

True enough. I wish the makers of the best screwdrivers would make a
wider range of tip sizes.


I think that the makers of the best screwdrivers are targeting
screws with the proper thickness slot for the width of the blade. The
torque required is defined by the diameter and thread pitch. This
defines the size of the head, and this the width and thickness of the
slot to have sufficient strength to handle these without bending.

Your narrow slotted screws are not really properly designed.
They were made with the size of slotting saw which the maker had on
hand -- and he did not want to buy a bunch of other thicknesses.

I think that some, though not all, screws with narrow slots have larger
heads than standard screws today. The traditional large "cheese" head is
becoming very uncommon.

It is also possible that in some cases narrow slots were intended to
signify that a high torque was not required (there are, of course, other
reasons for using a large diameter screw). But this is just my speculation.

Wera and Wiha are different brands. Wera screwdrivers have a distinctive
multicoloured handle with the dimensions of the tip printed on it. I've
been very impressed with them.


That sounds like a description of the Wiha ones in my belt
pouch. Handles are black with a red cap which pivots to allow you to
hold it pressed into the screw slot with a single fingertip. The
width and thickness are printed on the black part of the handle.

These are the ones I have:
http://www.screwfix.com/sfd/i/cat/31/p2613331_l.jpg


O.K. *Quite* colorful, and too large to fit my belt pouch
(which has my checkbook, several sizes of small screwdrivers, pens,
calculators, and usually a small pin vise all there on my belt).


The Wera screwdrivers also have a hexagonal shaft. It occurred to me
yesterday that this could be helpful when trying to modify one, as it
would help to ensure that the two ground faces are parallel.


Hmm ... I've seen some screwdrivers (SnapOn among them) which
have a hex forged just below the handle for allowing wrench to assist
with a really tight screw. (And yes, the screwdriver was forged tough
enough to handle that kind of abuse.)

Yes, they have a larger hexagonal section below the handle for this
purpose in addition to the hexagonal shaft. Also, the shaft goes right
the way through the plastic handle and emerges as a metal cap.


Hmm ... that latter feature is a design to survive abuse by
hammering on the end of the driver.

Indeed. Not something I generally do to them, though. It probably also
makes the handle plastic less likely to fail under torque at the
junction with the metal. But the Wera plastic is much less brittle than
that used on cheap screwdrivers, so there's an advantage to start with.

Having discovered that parallel ground screwdrivers are available, I am
a little surprised to find that the Wera screwdrivers are taper ground.
Next time I might look for parallel ground screwdrivers, although doing
a quick search I could only find one set by Pachmayr, and that was in
the US. The other results were for screwdriver bits.

Having said that, I rarely have problems with my taper ground
screwdrivers when the correct size is used in an undamaged slot with
adequate axial force.

I've got access to my father's lathe, but not a knurling tool.


Then consider getting a knurling tool for it. Ideally a
scissors style knurling tool, so you don't overstress the machine.

I just had a look at knurling tools. Good ones are relatively expensive.
A good one looks to be a similar price to that Brownells screwdriver
set, even including the postage.


Yes -- but you can then be equipped to make other tools using
it.


I think I am coming round to the idea of the Brownells set. It would get
a lot of use. They don't say much about the type of steel they're made
from, though. Some, but not all, screwdrivers advertise "Cr-V" or "Cr-V-Mo".


And some which advertise that are still poorly hardened and
tempered -- either too soft, or too brittle.

Or, in some cases, just stamped with the letters even though the steel
is nothing of the sort. Someone sued Rolson Tools in the UK over this,
and the company got fined a large sum of money.

Best wishes,

Chris

Leon Fisk wrote:
On Sat, 18 Oct 2008 13:46:37 +0000, Christopher Tidy
wrote:

snip

I think perhaps part of my reluctance is because I'm a bit of a
perfectionist. I like good, accurate tools and I'm not sure that I can
make a screwdriver of that standard. Good screwdrivers are really nice
to use. The way they snugly fit screw heads is satisfying.


Somebody else (most likely several) mentioned it already,
but try using small hex keys (Allen wrenches). They are
relatively inexpensive, hard and tough. If you grind/cut the
90 degree turn out of them a nice Pin Vice will hold them as
a handle. Being hex shaped they shouldn't slip in the Pin
Vice.

Don't worry about perfection, make something that will work
and get the job done. That will be satisfying enough

You might be right. I have got very keen on perfect projects and tools
lately. Some of the things I used to make were pretty crude, but I've
changed.

Chris

Gunner Asch wrote:
On Sun, 19 Oct 2008 13:53:02 +0000, Christopher Tidy
wrote:


Gunner Asch wrote:

On 19 Oct 2008 00:53:49 GMT, "DoN. Nichols"
wrote:



Perhaps what you need to do is to get a screwdriver with
interchangeable tips (here they have 1/4" hex shanks



The best are Chapman screwdriver kits

Thanks, Gunner. I will have a look to see if they sell especially thin
tipped screwdrivers.

Best wishes,

Chris



Chris..they sell ALL sizes of screwdriver bits. Some hair thin.

I use Chapmans exclusivly for working on firearms. Some of the very
old arms use hair thin slots in their screws, and one doesnt want a
screwdriver slipping and scratching the finish.

Gunner, I checked out the Chapman sets in detail. The 8900 set looked
the most suitable, so I studied the sizes in detail. It looked a good
buy and I almost bought it.

But I'm really glad I had the foresight to get my feeler gauge set out
and measure a few screw heads in the electrical equipment and clocks I
intend to work on. Some slots turned out to be 20/1000", perhaps half of
the total. The rest were 25/1000". The feeler gauges fitted the slots
really closely, so I'm pretty sure they're intended to be these sizes.
The gauge fitted better than a taper ground screwdriver bit. You could
be absolutely sure when you had the right size. I guess this is one of
the disadvantages of a taper ground bit.

So I need a set with bits which are 20/1000" thick. The Brownells set is
increasingly looking like the best option. But I'm going to have to
steal myself to make the purchase, as the delivery and likely import tax
will be high.

I notice that Brownells offer two handles. A magnetic handle and a
"clip-tip" handle. Initially I was inclined to go for the magnetic
handle so that I could use it to hold steel screws. But now I'm not sure
as I think the "clip-tip" handle may hold the bit more tightly. Some
magnetic handles do not hold the bit tightly enough. Anyone have an
opinion on which handle is better?

Thanks for all the advice.

Best wishes,

Chris

Christopher Tidy wrote in
:

But I'm really glad I had the foresight to get my feeler gauge set out
and measure a few screw heads in the electrical equipment and clocks I
intend to work on. Some slots turned out to be 20/1000", perhaps half of
the total. The rest were 25/1000". The feeler gauges fitted the slots
really closely, so I'm pretty sure they're intended to be these sizes.
The gauge fitted better than a taper ground screwdriver bit. You could
be absolutely sure when you had the right size. I guess this is one of
the disadvantages of a taper ground bit.

So I need a set with bits which are 20/1000" thick. The Brownells set is
increasingly looking like the best option. But I'm going to have to
steal myself to make the purchase, as the delivery and likely import tax
will be high.

I notice that Brownells offer two handles. A magnetic handle and a
"clip-tip" handle. Initially I was inclined to go for the magnetic
handle so that I could use it to hold steel screws. But now I'm not sure
as I think the "clip-tip" handle may hold the bit more tightly. Some
magnetic handles do not hold the bit tightly enough. Anyone have an
opinion on which handle is better?


Have you considered Cutting/grinding down feeler gauge blades to fit into
XACTO (or other hobby-type) knife handles?

While their blades may be the wrong thickness for you, the handles use a
collet to hold thin, flat blades.

On Sat, 25 Oct 2008 15:32:12 +0000, Christopher Tidy
wrote:

Leon Fisk wrote:
On Sat, 18 Oct 2008 13:46:37 +0000, Christopher Tidy
wrote:

snip

I think perhaps part of my reluctance is because I'm a bit of a
perfectionist. I like good, accurate tools and I'm not sure that I can
make a screwdriver of that standard. Good screwdrivers are really nice
to use. The way they snugly fit screw heads is satisfying.


Somebody else (most likely several) mentioned it already,
but try using small hex keys (Allen wrenches). They are
relatively inexpensive, hard and tough. If you grind/cut the
90 degree turn out of them a nice Pin Vice will hold them as
a handle. Being hex shaped they shouldn't slip in the Pin
Vice.

Don't worry about perfection, make something that will work
and get the job done. That will be satisfying enough

You might be right. I have got very keen on perfect projects and tools
lately. Some of the things I used to make were pretty crude, but I've
changed.

Chris


The Chapman screwdrivers also will hold Hex bits

Gunner

Whenever a Liberal utters the term "Common Sense approach"....grab your
wallet, your ass, and your guns because the sombitch is about to do
something damned nasty to all three of them.

On 2008-10-25, Christopher Tidy wrote:
DoN. Nichols wrote:

The problem I find with cheap screwdrivers is that they wear quickly,
and sometimes the tip becomes twisted.


Of course -- but a cheap screwdriver to modify to make a
one-time use screwdriver is often quite sufficient.

I do expect a set of thin screwdrivers to see a considerable amount of use.

O.K. Then go for good.

[ ... ]

it rapidly becomes unusable because of the quality of the material. My
experience has been that cheap screwdrivers are mostly a nuisance.


*One-time* use. If you expect to use it a lot, you start with
good materials.

This is why I was thinking of starting with a good quality screwdriver.
I would hate to grind one to exactly the right size, then find it only
lasted a short time.

Understood -- though a thin slot screw should not be using much
torque anyway.

[ ... ]

This did occur to me. It also occurred to me that if I could get 1/4"
hexagonal drill rod, this would allow me to make screwdriver bits
without needing to make a handle. But I couldn't find any.


Sure you can. Someone else already posted the source. Allen
keys (1/4" size, obviously). Cut off the elbow, and you have a short
piece and a longer piece. And they are normally good steel. You can
also buy a single size in boxes of 100 or 144 (depending on the size)
for a quite affordable price.

[ ... ]

Allen keys are a useful source, and one I hadn't thought of. Thanks for
that idea. But a box of 100 is about the same price as that thin bit set
from Brownells.

With the possibility of making several hundred (at least 200)
from the hex keys. Compare that to the number of bits in the Brownells
set.

Due to the unknown amount of time and experimentation it
will take me to make a good screwdriver bit, I am drawn towards the
Brownells set.

O.K. You still should *try* making a screwdriver of your own,
to see just how difficult is is (or isn't).

[ ... ]

I think in this case you're right. I do have a preference for fixed
blade screwdrivers when they're available, though. Interchangeable bits
aren't always held tightly in the handle, and the handle is usually a
bit bulkier.


But -- the interchangeable bits allow me to use them in a
electric screwdriver with adjustable torque limit. For some things, a
manual screwdriver is about as good, but when dealing with (for example)
changing out a set of cards in an old Sun 4/370 computer (3U VME bus),
you have two Allen head screws, M3x0.45 with about 1" of thread to back
out for each card -- and about 12 cards total in the system.
out for each card -- and about 12 cards total in the system. And you

[ ... ]

The electric screwdriver which I use was originally made by AEG,
and more recently Panasonic and Milwaukee -- same screwdriver, different
color plastic. :-)

I have a thing against electric screwdrivers. While they may be faster
and have an adjustable torque limit on some models, I find they give
poor control with slotted screws.

Put a sleeve over the head -- just large enough to cover the
diameter of the screw head. You can even get straight bits with a
spring-loaded collar for the purpose. The screwdriver which I made for
English system concertina endbox screws includes such a sleeve to keep
me from slipping and gouging the wood of the endbox. And I never use an
electric screwdriver with those, as the threads are fast enough and the
thread engagement is slow enough to be no problem.

As it turns out, I don't often use slotted screws. When I am
building something from scratch, I tend to choose Allen head cap screws
and button head screws with Allen sockets for most things, with security
Torx used for a few things. And I often work on things fitted with a
lot of Phillips screws, but seldom slotted ones these days. And for
wood screws, I prefer the Robertson (square drive) screws.

I just prefer to use a normal
screwdriver and estimate the required torque. I have only once damaged a
thread in this way, and that was a long time ago, so I don't think I'm
doing too badly.

I just used it this evening for swapping subassemblies between
two Exabyte Mammoth (8900) computer tape drives. Almost everything in
there uses screws of 2mm diameter (1.96mm from measuring a typical one)
and the lowest torque setting (1) on this driver releases at the right
point to avoid overdriving these into the relatively soft metal of the
chassis. The more serious problem was finding the right size (T6) of
Torx bit -- but they can be found in 1/4" hex shank size.

There are two intermediate clicks between (1) and (2) on the
electric screwdriver (and it goes up to (6)). I use the (2) setting
commonly on both the 6-32 screws and the fairly common 3mm ones used for
mounting tape and CD drives in computers.

I also have a set of two manual torque limiting screwdrivers by
Utica. 6-30 Lb-In, and 0-100 Oz-In. Both of these also accept 1/4" hex
shank bits (as well as adaptors to a 1/4" square drive for sockets.)
The most frequent use for these (aside from the spare of one which I
keep with my best English system concertina) is in removing and
replacing CPU modules in Sun Blade 1000/2000 systems and Sun Fire 280R
(same system board and CPU modules). Sun considers the torque important
enough here so they supply torque measuring screwdrivers with the
systems -- the one with the Sun Blade 2000 and the Sun Fire 280R is
better than the rather simple design in the Sun Blade 1000. (According
to the manuals, later systems were shipped without *any* torque driver,
but the torque drivers were supplied when you bought replacement or
upgrade CPUs. They also clearly spell out the needed torque (5 Lb-In)
for those who have a general purpose torque screwdriver such as mine.
The jackscrews take a Robertson (square) bit, and are marked with a
fluorescent green ring around the screw holes -- matching the color of
the torque screwdriver body, or the plastic carrier holding the earlier
design (a ring which closes at the proper torque) which slides between
the two disk drives in the system.

I had wondered about buying interchangeable bits and attempting to
modify them using a half round file, but I'm not sure if they could
readily be filed.


If not, they can be ground.

[ ... ]

Your narrow slotted screws are not really properly designed.
They were made with the size of slotting saw which the maker had on
hand -- and he did not want to buy a bunch of other thicknesses.

I think that some, though not all, screws with narrow slots have larger
heads than standard screws today. The traditional large "cheese" head is
becoming very uncommon.

It is also possible that in some cases narrow slots were intended to
signify that a high torque was not required (there are, of course, other
reasons for using a large diameter screw). But this is just my speculation.

Yes. Possible.

When were these made? And where? IIRC they are in clocks, but
from back in the period when most hardware was custom made by the
clockmaker, or from when production lines and supplies were more common?

[ ... ]

Yes, they have a larger hexagonal section below the handle for this
purpose in addition to the hexagonal shaft. Also, the shaft goes right
the way through the plastic handle and emerges as a metal cap.


Hmm ... that latter feature is a design to survive abuse by
hammering on the end of the driver.

Indeed. Not something I generally do to them, though.

I did qualify that treatment as abuse, after all.

It probably also
makes the handle plastic less likely to fail under torque at the
junction with the metal. But the Wera plastic is much less brittle than
that used on cheap screwdrivers, so there's an advantage to start with.

I've never had even a cheap screwdriver handle break on me.
Granted, I don't pound on the ends with a hammer. :-)

Having discovered that parallel ground screwdrivers are available, I am
a little surprised to find that the Wera screwdrivers are taper ground.
Next time I might look for parallel ground screwdrivers, although doing
a quick search I could only find one set by Pachmayr, and that was in
the US. The other results were for screwdriver bits.

Having said that, I rarely have problems with my taper ground
screwdrivers when the correct size is used in an undamaged slot with
adequate axial force.

Indeed so.

[ ... ]

I think I am coming round to the idea of the Brownells set. It would get
a lot of use. They don't say much about the type of steel they're made
from, though. Some, but not all, screwdrivers advertise "Cr-V" or "Cr-V-Mo".


And some which advertise that are still poorly hardened and
tempered -- either too soft, or too brittle.

Or, in some cases, just stamped with the letters even though the steel
is nothing of the sort. Someone sued Rolson Tools in the UK over this,
and the company got fined a large sum of money.

There have been similar problems with drill bits from China --
marked as M2 HSS -- but being nothing of the sort. Some have caught
partway through the drilling and been turned into reverse spiral bits. :-)

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

On 2008-10-25, Christopher Tidy wrote:
Gunner Asch wrote:

[ ... ]

I use Chapmans exclusivly for working on firearms. Some of the very
old arms use hair thin slots in their screws, and one doesnt want a
screwdriver slipping and scratching the finish.

Gunner, I checked out the Chapman sets in detail. The 8900 set looked
the most suitable, so I studied the sizes in detail. It looked a good
buy and I almost bought it.

But I'm really glad I had the foresight to get my feeler gauge set out
and measure a few screw heads in the electrical equipment and clocks I
intend to work on. Some slots turned out to be 20/1000", perhaps half of
the total. The rest were 25/1000".

More commonly written 0.020" and 0.025"

The feeler gauges fitted the slots
really closely, so I'm pretty sure they're intended to be these sizes.

What this really means is that the slots were cut by milling
cutters of those thicknesses. I've set up to make screws for English
system concertinas (I've settled on M3.5x0.45 since the original thread
matches no current standard), and among other operations, I made a block
which will hold 20 screws in four rows. I have four slotting cutters on
the horizontal mill's arbor so I can slot all of them in a single pass.
IIRC, the cutter thickness for these is 0.0156" (1/64th") -- selected to
match the slots of older concertina endbox screws. Once you are set up
with a single slitting saw size, you really don't want to change
frequently, so they used what they had for all the screws, instead of
making each to a dimension appropriate to the job.

Many modern screws are made by "heading" the stock which carried
the thread -- bashing it into a die which causes it to take on the
appropriate shape -- and often also drives the slot into it at the same
time, instead of cutting it. Given that, such modern screws are likely
to have slots which are a better fit to a taper-ground screwdriver than
to a parallel ground one. :-)

The gauge fitted better than a taper ground screwdriver bit. You could
be absolutely sure when you had the right size. I guess this is one of
the disadvantages of a taper ground bit.

It depends on how the screws were made. Clock screws will have
the slot cut by slitting saws in a milling machine (or a clockmaker's
lathe acting as a milling machine).

So I need a set with bits which are 20/1000" thick. The Brownells set is
increasingly looking like the best option. But I'm going to have to
steal myself to make the purchase,

You mean that you will have to illegally take other's property?
Or did you really mean "steel yourself"? :-)

as the delivery and likely import tax
will be high.

I notice that Brownells offer two handles. A magnetic handle and a
"clip-tip" handle. Initially I was inclined to go for the magnetic
handle so that I could use it to hold steel screws. But now I'm not sure
as I think the "clip-tip" handle may hold the bit more tightly. Some
magnetic handles do not hold the bit tightly enough. Anyone have an
opinion on which handle is better?

I would avoid the magnetic style when working with clocks and
tape recorders, as both can be damaged by magnetic fields. In a clock
(or a watch) the magnetic field can cause alternate layers of the spiral
spring on the balance wheel to stick together. (Not a problem with
pendulum clocks, of course), and with tape recorders, the magnetic field
can magnetize the tape heads resulting in a serious increase in hiss.

But the selection really is normally a function of the bits
being purchased. The ones to be held magnetically are very short bits,
while those intended to be held by the "clip-tip" are longer, and have a
groove turned near the end into which a ball detent drops to keep the
tip from falling out. I tend to use the latter design most of the time,
but you can get magnetic holders which will fit into the "clip-tip"
style body when you need to handle less common bits. For example, I
have a set of bits which contains 100 pieces, of which all but 4 are
different sizes of bits. There are duplicates of the most frequently
used sizes and style -- 5 copies of then #2 Phllips, while only one each
of #0, #1 and #3. Same for the Pozidrive bits (Phillips with a extra
set of points in the inner folds of the socket).

1 each of the four Robertson (square drive) bits #0 through #3.

9 slotted bits -- in metric widths. The 3mm width is 0.020"
thick. The 4mm and 4.5mm are 0.032" thick. going up to 0.058" for the
8mm one.

Then four slotted bits with split points.

9 Torx bits from T8 to T45 (The smallest is not small enough for
the Exabyte drives -- but I have those from other sources).

9 Security Tork bits covering the same range, but with a hole
in the end to clear a pin in the screw's socket.

#6, 8, and 10 offset Phillips (the wings are not true radii.

#1, 2, 3, and 4 tri-wing -- like the offset Phillips, but only
three blades.

Metric Allen from 1.5mm to 8mm

Imperial Allen from 1/16" to 1/4"

Three "clutch tip" bits, #1, 2, and 3

Three spline bits -- M5, M6, and M8

Metric Security Allen from 2mm to 6mm

Imperial Security Allen from 5/64 to 5/32 (in 64th).

In addition to these, there is a clip-tip to magnetic holder,
A Y driver -- intended to drive cup hooks and small eyes.
a 1" long and a 2" long adaptor from 1/4" hex to 1/4" square
drive.

And -- a coupler going the other way from 1/4" square to 1/4"
hex.

All in all -- a rather useful set to cover the strange ones
which I don't have otherwise. I already had the tri-wing and the offset
Phillips (as well as normal Torx, Allen and the security versions of
both. But the Clutch (once common in automobile assembly in the USA),
the spline bits, and the Metric Allen bits.

What there is *not* in the set is any form of handle. You are
presumed to have the handle, or the electric screwdriver, or both
already. (Actually -- I even have an adaptor from my Gerber folding
pliers to the hex.)

All in all -- the hex bits are a good thing to have, since you
can find weird ones in hex bits more easily than with a full shank and
handle. And you can certainly carry a lot more styles in a collection
of hex bits with a single handle than a full set of screwdrivers with
handles.

The Security Allen used to be used on PC power supplies by some
makers -- to keep users out of the power supply. :-)

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

DoN. Nichols wrote:

But I'm really glad I had the foresight to get my feeler gauge set out
and measure a few screw heads in the electrical equipment and clocks I
intend to work on. Some slots turned out to be 20/1000", perhaps half of
the total. The rest were 25/1000".


More commonly written 0.020" and 0.025"

From the point of view of consistency, I feel a bit bad describing a
screwdriver tip as 3/8" x 0.025". I was using fractions for the larger
dimension earlier, so I decided to be consistent. Using fractions and
decimals together seems weird.

The feeler gauges fitted the slots
really closely, so I'm pretty sure they're intended to be these sizes.


What this really means is that the slots were cut by milling
cutters of those thicknesses. I've set up to make screws for English
system concertinas (I've settled on M3.5x0.45 since the original thread
matches no current standard), and among other operations, I made a block
which will hold 20 screws in four rows. I have four slotting cutters on
the horizontal mill's arbor so I can slot all of them in a single pass.
IIRC, the cutter thickness for these is 0.0156" (1/64th") -- selected to
match the slots of older concertina endbox screws. Once you are set up
with a single slitting saw size, you really don't want to change
frequently, so they used what they had for all the screws, instead of
making each to a dimension appropriate to the job.

Strange size. I thought the standard M3.5 pitches were 0.35 mm (fine)
and 0.6 mm (coarse).

Many modern screws are made by "heading" the stock which carried
the thread -- bashing it into a die which causes it to take on the
appropriate shape -- and often also drives the slot into it at the same
time, instead of cutting it. Given that, such modern screws are likely
to have slots which are a better fit to a taper-ground screwdriver than
to a parallel ground one. :-)

Good point. I imagine that if the slot is formed in a die, it will end
up being slightly tapered.

The gauge fitted better than a taper ground screwdriver bit. You could
be absolutely sure when you had the right size. I guess this is one of
the disadvantages of a taper ground bit.


It depends on how the screws were made. Clock screws will have
the slot cut by slitting saws in a milling machine (or a clockmaker's
lathe acting as a milling machine).


So I need a set with bits which are 20/1000" thick. The Brownells set is
increasingly looking like the best option. But I'm going to have to
steal myself to make the purchase,


You mean that you will have to illegally take other's property?
Or did you really mean "steel yourself"? :-)

You're right. I did mean "steel myself". Thanks for correcting me!

as the delivery and likely import tax
will be high.

I notice that Brownells offer two handles. A magnetic handle and a
"clip-tip" handle. Initially I was inclined to go for the magnetic
handle so that I could use it to hold steel screws. But now I'm not sure
as I think the "clip-tip" handle may hold the bit more tightly. Some
magnetic handles do not hold the bit tightly enough. Anyone have an
opinion on which handle is better?


I would avoid the magnetic style when working with clocks and
tape recorders, as both can be damaged by magnetic fields. In a clock
(or a watch) the magnetic field can cause alternate layers of the spiral
spring on the balance wheel to stick together. (Not a problem with
pendulum clocks, of course), and with tape recorders, the magnetic field
can magnetize the tape heads resulting in a serious increase in hiss.

I hadn't thought of this. Thanks for pointing it out. I'll probably go
with the "clip-tip" style of handle now.

But the selection really is normally a function of the bits
being purchased. The ones to be held magnetically are very short bits,
while those intended to be held by the "clip-tip" are longer, and have a
groove turned near the end into which a ball detent drops to keep the
tip from falling out. I tend to use the latter design most of the time,
but you can get magnetic holders which will fit into the "clip-tip"
style body when you need to handle less common bits. For example, I
have a set of bits which contains 100 pieces, of which all but 4 are
different sizes of bits. There are duplicates of the most frequently
used sizes and style -- 5 copies of then #2 Phllips, while only one each
of #0, #1 and #3. Same for the Pozidrive bits (Phillips with a extra
set of points in the inner folds of the socket).

It seems that the Brownells bits will fit either type of handle.

Many thanks for the advice.

Best wishes,

Chris

DoN. Nichols wrote:

snip

Allen keys are a useful source, and one I hadn't thought of. Thanks for
that idea. But a box of 100 is about the same price as that thin bit set
from Brownells.


With the possibility of making several hundred (at least 200)
from the hex keys. Compare that to the number of bits in the Brownells
set.

True enough. But to be honest, I suspect that I wouldn't need to make
more than 20 bits (in a reasonable length of time, anyway). So the
majority of those Allen keys will sit on a shelf unused.

Due to the unknown amount of time and experimentation it
will take me to make a good screwdriver bit, I am drawn towards the
Brownells set.


O.K. You still should *try* making a screwdriver of your own,
to see just how difficult is is (or isn't).

I will. I actually feel a bit bad not making the screwdrivers, but
there's always a point at which you have to decide what you're going to
make and what you're going to buy. Right now I have too many projects on
the go, and making screwdrivers seems less appealing than the other
projects I'm working on. But when I find a worn screwdriver that I no
longer want, I'll have a go at grinding it and see how neat it turns out.

I think in this case you're right. I do have a preference for fixed
blade screwdrivers when they're available, though. Interchangeable bits
aren't always held tightly in the handle, and the handle is usually a
bit bulkier.


But -- the interchangeable bits allow me to use them in a
electric screwdriver with adjustable torque limit. For some things, a
manual screwdriver is about as good, but when dealing with (for example)
changing out a set of cards in an old Sun 4/370 computer (3U VME bus),
you have two Allen head screws, M3x0.45 with about 1" of thread to back
out for each card -- and about 12 cards total in the system.
out for each card -- and about 12 cards total in the system. And you


[ ... ]


The electric screwdriver which I use was originally made by AEG,
and more recently Panasonic and Milwaukee -- same screwdriver, different
color plastic. :-)

I have a thing against electric screwdrivers. While they may be faster
and have an adjustable torque limit on some models, I find they give
poor control with slotted screws.


Put a sleeve over the head -- just large enough to cover the
diameter of the screw head. You can even get straight bits with a
spring-loaded collar for the purpose. The screwdriver which I made for
English system concertina endbox screws includes such a sleeve to keep
me from slipping and gouging the wood of the endbox. And I never use an
electric screwdriver with those, as the threads are fast enough and the
thread engagement is slow enough to be no problem.

Doesn't the sleeve prevent you from seeing if the bit is located in the
slot?

As it turns out, I don't often use slotted screws. When I am
building something from scratch, I tend to choose Allen head cap screws
and button head screws with Allen sockets for most things, with security
Torx used for a few things. And I often work on things fitted with a
lot of Phillips screws, but seldom slotted ones these days. And for
wood screws, I prefer the Robertson (square drive) screws.

Personally I think that sometimes a slotted screw head is needed for
appearance. On some devices, a Phillips or Allen head looks wrong.

I've never seen square drive wood screws. Must be an American thing.

I just prefer to use a normal
screwdriver and estimate the required torque. I have only once damaged a
thread in this way, and that was a long time ago, so I don't think I'm
doing too badly.


I just used it this evening for swapping subassemblies between
two Exabyte Mammoth (8900) computer tape drives. Almost everything in
there uses screws of 2mm diameter (1.96mm from measuring a typical one)
and the lowest torque setting (1) on this driver releases at the right
point to avoid overdriving these into the relatively soft metal of the
chassis. The more serious problem was finding the right size (T6) of
Torx bit -- but they can be found in 1/4" hex shank size.

There are two intermediate clicks between (1) and (2) on the
electric screwdriver (and it goes up to (6)). I use the (2) setting
commonly on both the 6-32 screws and the fairly common 3mm ones used for
mounting tape and CD drives in computers.

I also have a set of two manual torque limiting screwdrivers by
Utica. 6-30 Lb-In, and 0-100 Oz-In. Both of these also accept 1/4" hex
shank bits (as well as adaptors to a 1/4" square drive for sockets.)
The most frequent use for these (aside from the spare of one which I
keep with my best English system concertina) is in removing and
replacing CPU modules in Sun Blade 1000/2000 systems and Sun Fire 280R
(same system board and CPU modules). Sun considers the torque important
enough here so they supply torque measuring screwdrivers with the
systems -- the one with the Sun Blade 2000 and the Sun Fire 280R is
better than the rather simple design in the Sun Blade 1000. (According
to the manuals, later systems were shipped without *any* torque driver,
but the torque drivers were supplied when you bought replacement or
upgrade CPUs. They also clearly spell out the needed torque (5 Lb-In)
for those who have a general purpose torque screwdriver such as mine.
The jackscrews take a Robertson (square) bit, and are marked with a
fluorescent green ring around the screw holes -- matching the color of
the torque screwdriver body, or the plastic carrier holding the earlier
design (a ring which closes at the proper torque) which slides between
the two disk drives in the system.

Sometime I might get a manual torque limiting screwdriver, but for the
time being I'm managing without.

Your narrow slotted screws are not really properly designed.
They were made with the size of slotting saw which the maker had on
hand -- and he did not want to buy a bunch of other thicknesses.

I think that some, though not all, screws with narrow slots have larger
heads than standard screws today. The traditional large "cheese" head is
becoming very uncommon.

It is also possible that in some cases narrow slots were intended to
signify that a high torque was not required (there are, of course, other
reasons for using a large diameter screw). But this is just my speculation.


Yes. Possible.

When were these made? And where? IIRC they are in clocks, but
from back in the period when most hardware was custom made by the
clockmaker, or from when production lines and supplies were more common?

Mostly on electrical equipment made between the 1930s and 1950s,
together with a few on clocks. You could certainly buy those big "cheese
head" screws in England up until recently. I bought some 0 BA screws in
that style a few years back, but when I went back for more, they were no
longer available.

Yes, they have a larger hexagonal section below the handle for this
purpose in addition to the hexagonal shaft. Also, the shaft goes right
the way through the plastic handle and emerges as a metal cap.


Hmm ... that latter feature is a design to survive abuse by
hammering on the end of the driver.

Indeed. Not something I generally do to them, though.


I did qualify that treatment as abuse, after all.


It probably also
makes the handle plastic less likely to fail under torque at the
junction with the metal. But the Wera plastic is much less brittle than
that used on cheap screwdrivers, so there's an advantage to start with.


I've never had even a cheap screwdriver handle break on me.
Granted, I don't pound on the ends with a hammer. :-)

The ones I've had break were made from a clear yellow plastic. When the
plastic broke, it looked almost like glass. I didn't hammer them. It was
torque in normal use which caused them to break.

Best wishes,

Chris

RAM³ wrote:
Christopher Tidy wrote in
:


But I'm really glad I had the foresight to get my feeler gauge set out
and measure a few screw heads in the electrical equipment and clocks I
intend to work on. Some slots turned out to be 20/1000", perhaps half of
the total. The rest were 25/1000". The feeler gauges fitted the slots
really closely, so I'm pretty sure they're intended to be these sizes.
The gauge fitted better than a taper ground screwdriver bit. You could
be absolutely sure when you had the right size. I guess this is one of
the disadvantages of a taper ground bit.

So I need a set with bits which are 20/1000" thick. The Brownells set is
increasingly looking like the best option. But I'm going to have to
steal myself to make the purchase, as the delivery and likely import tax
will be high.

I notice that Brownells offer two handles. A magnetic handle and a
"clip-tip" handle. Initially I was inclined to go for the magnetic
handle so that I could use it to hold steel screws. But now I'm not sure
as I think the "clip-tip" handle may hold the bit more tightly. Some
magnetic handles do not hold the bit tightly enough. Anyone have an
opinion on which handle is better?



Have you considered Cutting/grinding down feeler gauge blades to fit into
XACTO (or other hobby-type) knife handles?

While their blades may be the wrong thickness for you, the handles use a
collet to hold thin, flat blades.

For the larger sized screws, I think it would be difficult to exert
sufficient torque using an X-Acto handle.

Best wishes,

Chris