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.

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

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

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

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 ---

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

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.

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