Hi, I hope you are all well.

I'm relatively new to this so please accept my apologies if I make
some errors.

I have previously had some experience, under limited supervision from
a trained engineer, on the Bridgeport. I've now purchased one for my
own use which has been supplied with some tooling.

All of the (rather ragged) end mills are screw shank and there is a
chuck with various diameter tapped holders (collets?). Also supplied
was a box of R8 collets (2mm - 20mm from memory).

I've previously used the screw-shank variants so I'm comfortable with
them however I have no experience with the collets.

A few questions if I may:

a) Which method is better?

b) Dependant on a suitable diameter collet, do all "Plain shank" end
mills fit in the R8 collets?

c) When I purchase new end-mills, which of the above would you
recommend?

Thanks & regards,
Mike

MikeG wrote:
Hi, I hope you are all well.

I'm relatively new to this so please accept my apologies if I make
some errors.

I have previously had some experience, under limited supervision from
a trained engineer, on the Bridgeport. I've now purchased one for my
own use which has been supplied with some tooling.

All of the (rather ragged) end mills are screw shank and there is a
chuck with various diameter tapped holders (collets?). Also supplied
was a box of R8 collets (2mm - 20mm from memory).

I've previously used the screw-shank variants so I'm comfortable with
them however I have no experience with the collets.

A few questions if I may:

a) Which method is better?

b) Dependant on a suitable diameter collet, do all "Plain shank" end
mills fit in the R8 collets?

c) When I purchase new end-mills, which of the above would you
recommend?

Thanks & regards,
Mike

Mike,

Sounds like you have a Clarkson autolock holder, are you familiar with
their use?.

a) The Clarkson holder for the screwed shank cutters is better than
collets as the cutter can't pull out under heavy cuts like it can with a
collet.

b) As far as I know all cutters, be they screwed shank, Weldon (set
screw retention), or plain shank are OK in collets. I have threaded
shank and a few Weldon types and regularly use them in collets when the
guaranteed retention given by the Clarkson holder is not required. Just
make sure the cutter is inserted so the collet is holding the plain section.

c) Depends what you're doing. If you're not taking heavy cuts then the
threaded shanks for the Clarkson are not required but I buy most of mine
as threaded shank in the larger sizes. 16mm being the largest I normally
use. Not noticed much difference in the price, I often buy tools when
on sale from J&L UK.

Hope that helps.

On Wed, 10 Dec 2008 11:42:53 +0000, David Billington
wrote:

MikeG wrote:
Hi, I hope you are all well.

I'm relatively new to this so please accept my apologies if I make
some errors.

I have previously had some experience, under limited supervision from
a trained engineer, on the Bridgeport. I've now purchased one for my
own use which has been supplied with some tooling.

All of the (rather ragged) end mills are screw shank and there is a
chuck with various diameter tapped holders (collets?). Also supplied
was a box of R8 collets (2mm - 20mm from memory).

I've previously used the screw-shank variants so I'm comfortable with
them however I have no experience with the collets.

A few questions if I may:

a) Which method is better?

b) Dependant on a suitable diameter collet, do all "Plain shank" end
mills fit in the R8 collets?

c) When I purchase new end-mills, which of the above would you
recommend?

Thanks & regards,
Mike

Mike,

Sounds like you have a Clarkson autolock holder, are you familiar with
their use?.

a) The Clarkson holder for the screwed shank cutters is better than
collets as the cutter can't pull out under heavy cuts like it can with a
collet.

b) As far as I know all cutters, be they screwed shank, Weldon (set
screw retention), or plain shank are OK in collets. I have threaded
shank and a few Weldon types and regularly use them in collets when the
guaranteed retention given by the Clarkson holder is not required. Just
make sure the cutter is inserted so the collet is holding the plain section.

c) Depends what you're doing. If you're not taking heavy cuts then the
threaded shanks for the Clarkson are not required but I buy most of mine
as threaded shank in the larger sizes. 16mm being the largest I normally
use. Not noticed much difference in the price, I often buy tools when
on sale from J&L UK.

Hope that helps.

Hi David,

Many thanks for your detailed reply. I have noted your comments.

I've used the screw shank cutters and holder before but I didn't know
the correct name for them - thanks. Looking on the web, the autolock
inserts appear to be threaded but the ones supplied with my machine
aren't. They just slip into the holder and are held in place by the
retaining collar, tightened by a spanner. Is this still a "Clarkson
autolock"?

The engineer who was showing me the ropes recommended that the screwed
end of the cutter protrude slightly (maybe 1mm+) from the end of the
holder before it was inserted into the sleeve and tightened. Is this
correct?

I haven't managed to break anything yet and I'm keen to keep it that
way!

Kind regards,
Mike

MikeG wrote:
On Wed, 10 Dec 2008 11:42:53 +0000, David Billington
wrote:


MikeG wrote:

Hi, I hope you are all well.

I'm relatively new to this so please accept my apologies if I make
some errors.

I have previously had some experience, under limited supervision from
a trained engineer, on the Bridgeport. I've now purchased one for my
own use which has been supplied with some tooling.

All of the (rather ragged) end mills are screw shank and there is a
chuck with various diameter tapped holders (collets?). Also supplied
was a box of R8 collets (2mm - 20mm from memory).

I've previously used the screw-shank variants so I'm comfortable with
them however I have no experience with the collets.

A few questions if I may:

a) Which method is better?

b) Dependant on a suitable diameter collet, do all "Plain shank" end
mills fit in the R8 collets?

c) When I purchase new end-mills, which of the above would you
recommend?

Thanks & regards,
Mike


Mike,

Sounds like you have a Clarkson autolock holder, are you familiar with
their use?.

a) The Clarkson holder for the screwed shank cutters is better than
collets as the cutter can't pull out under heavy cuts like it can with a
collet.

b) As far as I know all cutters, be they screwed shank, Weldon (set
screw retention), or plain shank are OK in collets. I have threaded
shank and a few Weldon types and regularly use them in collets when the
guaranteed retention given by the Clarkson holder is not required. Just
make sure the cutter is inserted so the collet is holding the plain section.

c) Depends what you're doing. If you're not taking heavy cuts then the
threaded shanks for the Clarkson are not required but I buy most of mine
as threaded shank in the larger sizes. 16mm being the largest I normally
use. Not noticed much difference in the price, I often buy tools when
on sale from J&L UK.

Hope that helps.


Hi David,

Many thanks for your detailed reply. I have noted your comments.

I've used the screw shank cutters and holder before but I didn't know
the correct name for them - thanks. Looking on the web, the autolock
inserts appear to be threaded but the ones supplied with my machine
aren't. They just slip into the holder and are held in place by the
retaining collar, tightened by a spanner. Is this still a "Clarkson
autolock"?

Mike,

I jumped to the conclusion you had a Clarkson autolock holder when
you said threaded shank cutters but was wrong by the sound of it. Have a
look here for some different collet types.
http://www.arceurotrade.co.uk/Catalogue/Collets . At a guess I might
think you have an ER collet holder as they don't have threads in them
and are quite common, see
http://www.arceurotrade.co.uk/Catalo...-Collet-Chucks .

The engineer who was showing me the ropes recommended that the screwed
end of the cutter protrude slightly (maybe 1mm+) from the end of the
holder before it was inserted into the sleeve and tightened. Is this
correct?

Sounds good.

I haven't managed to break anything yet and I'm keen to keep it that
way!

Always a good strategy.

Cheers,

Dave

Kind regards,
Mike

On 2008-12-10, MikeG wrote:
Hi, I hope you are all well.

I'm relatively new to this so please accept my apologies if I make
some errors.

I have previously had some experience, under limited supervision from
a trained engineer, on the Bridgeport. I've now purchased one for my
own use which has been supplied with some tooling.

Congratulations!

All of the (rather ragged) end mills are screw shank and there is a
chuck with various diameter tapped holders (collets?). Also supplied
was a box of R8 collets (2mm - 20mm from memory).

O.K. There are four ways that I know of to hold end mills in a
Bridgeport, and one of them is quite uncommon in the USA, though quite
common in the UK. I'll describe that one first:

1) Clarkson end mill holders:

The last few mm of the mill's shank is threaded, and threads
into collets which fit into the holder. The holder has a
projecting center which bears on the center hole of the end
mill.

I've got a couple of sizes of the holders, and none of the end
mills for the NTMB 40 spindle of my Nichols horizontal mill.

This style of holder has the advantage that the end mill cannot
shift its projection during cutting loads (unlike the R8
collets.

There are collets available for this to fit metric size shanks,
and fractional inch size shanks. The ones which I have are all
fractional inch sizes. I wish that I could buy the collets at
reasonable prices here in the USA -- just so I can try it at
least. :-)

2) Shrink-fit end mill holders:

Also uncommon -- except in serious production shops in the USA
(and perhaps elsewhere). The hole in the end mill holder is
just a little smaller than the diameter of the shank, so the
holder is heated and the end mill is inserted before the holder
can shrink again. I've never used one of these, but I have the
feeling that once an end mill is inserted, it is there for life.

And I don't know whether these have setscrews in addition to the
shrink fit or not.

3) Setscrew end mill holders:

The best bet in the USA where the Clarkson holders and end mills
are not readily available. The end mill is inserted, and the
flat-bottomed setscrew with a bevel edge is tightened. The
bevel on the end of the setscrew encounters a matching bevel at
the top end of the Weldon falt onto which the screw tightens.
This keeps the spiral of the end mill from pulling it down and
thus starting to cut deeper than you planned.

4) R8 collets:

The most common US way of holding end mills -- but the spiral of
the flutes can cause the end mill to walk down in the grip of
the collet during heavy cuts, resulting in damage to the
workpiece, and occasionally damage to the table or the vise as
well.

Note that R8 collets have a very small range of contraction, so
you can't mix metric collets and inch shanks or vice versa.

I've previously used the screw-shank variants so I'm comfortable with
them however I have no experience with the collets.

A few questions if I may:

a) Which method is better?

To my mind, the Clarkson system -- if that is one of what you
have. Your description was a little unclear to me.

Second would be the setscrew type of end mill holders, if you
can get end mills with Weldon flats.

Third (for convenience) would be the R8 collets -- but be
careful when taking heavy cuts.

Forth would be the shrink fit holders -- if only because a
hobby user can't usually afford to expend an end mill holder when an end
mill is no longer useful.

b) Dependant on a suitable diameter collet, do all "Plain shank" end
mills fit in the R8 collets?

Metric size end mill shanks fit the metric R8 collets (which it
appears you have). Fractional inch end mill shanks fit fractional inch
R8 collets. *Don't* try to stretch a collet to hold a larger size, it
will only lead to disaster.

c) When I purchase new end-mills, which of the above would you
recommend?

If you have the Clarkson holders, go that way. I don't know the
relative cost between Clarkson end mills, ones with Weldon flats, and
ones with purely cylindrical shanks, but if the cost of the Clarksons is
not prohibitive, it is more likely to prevent damage to a workpiece
which already has many hours of work invested in it.

While you are at it -- you also want 2-flute end mills for
cutting slots, and ones with more flutes (four and six are common in my
collection) for milling from the side.

There are also "roughing" end mills for fast material removal,
and the standard ones for everything else.

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 in message
...

snip

2) Shrink-fit end mill holders:

Also uncommon -- except in serious production shops in the USA
(and perhaps elsewhere). The hole in the end mill holder is
just a little smaller than the diameter of the shank, so the
holder is heated and the end mill is inserted before the holder
can shrink again. I've never used one of these, but I have the
feeling that once an end mill is inserted, it is there for life.

And I don't know whether these have setscrews in addition to the
shrink fit or not.

For the record, these are pretty pricey for hobby work, and their real
payoff is in handling tools for use in high-speed mills -- 10,000 rpm and
up.

Also for the record, the heaters, which use induction heating, will seat or
release carbide-shank tools without trouble. But only the best ones (mostly
made by Bilz, often re-branded by other tooling makers) will reliably
*release* a HSS-shank tool. The coefficient of thermal expansion is about
the same for tool and holder, and it requires a really quick heating to
expand the holder without swelling the tool shank too much to release.

I think the prices will make most hobbyists' eyes roll back in their heads.
But they're really slick and they work great.

--
Ed Huntress

DoN. Nichols writes:

O.K. There are four ways that I know of to hold end mills in a
Bridgeport,

Should ER collets be a fifth?

On 2008-12-11, Richard J Kinch wrote:
DoN. Nichols writes:

O.K. There are four ways that I know of to hold end mills in a
Bridgeport,

Should ER collets be a fifth?

Perhaps. It depends on how much better they are at keeping the
cutters from creeping down under heavy cuts. If they are the same, just
lump them with "R8"s with a higher cost added on. :-)

There are also the quick-change tool systems, including the one
for the Series-I CNC version of the Bridgeport which uses NTMB holders,
which can be endmill holders or collet type.

There is another quick-change system which fits into the
standard R8 spindle.

But both of those are more likely to be found on CNC versions of
the Bridgeports, not on manual ones.

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 Wed, 10 Dec 2008 12:53:19 +0000, David Billington
wrote:

MikeG wrote:
On Wed, 10 Dec 2008 11:42:53 +0000, David Billington
wrote:

snip

Hi David,

Many thanks for your detailed reply. I have noted your comments.

I've used the screw shank cutters and holder before but I didn't know
the correct name for them - thanks. Looking on the web, the autolock
inserts appear to be threaded but the ones supplied with my machine
aren't. They just slip into the holder and are held in place by the
retaining collar, tightened by a spanner. Is this still a "Clarkson
autolock"?

Mike,

I jumped to the conclusion you had a Clarkson autolock holder when
you said threaded shank cutters but was wrong by the sound of it. Have a
look here for some different collet types.
http://www.arceurotrade.co.uk/Catalogue/Collets . At a guess I might
think you have an ER collet holder as they don't have threads in them
and are quite common, see
http://www.arceurotrade.co.uk/Catalo...-Collet-Chucks .

The engineer who was showing me the ropes recommended that the screwed
end of the cutter protrude slightly (maybe 1mm+) from the end of the
holder before it was inserted into the sleeve and tightened. Is this
correct?

Sounds good.

I haven't managed to break anything yet and I'm keen to keep it that
way!

Always a good strategy.

Cheers,

Dave

Kind regards,
Mike




Hi Dave

Again, thanks for taking the time to reply.

I may have fed you a bum steer with my description of the collet - I
think it is a Clarkson Autolock - this is link to a picture.

http://www.mgarner.co.uk/Collet.jpg

As an aside, please could you confirm that this is a "J" type head?

http://www.mgarner.co.uk/Bridgeport.jpg

Thanks & kind regards,
Mike

On 11 Dec 2008 04:01:15 GMT, "DoN. Nichols"
wrote:

On 2008-12-10, MikeG wrote:
Hi, I hope you are all well.

I'm relatively new to this so please accept my apologies if I make
some errors.

I have previously had some experience, under limited supervision from
a trained engineer, on the Bridgeport. I've now purchased one for my
own use which has been supplied with some tooling.

Congratulations!

All of the (rather ragged) end mills are screw shank and there is a
chuck with various diameter tapped holders (collets?). Also supplied
was a box of R8 collets (2mm - 20mm from memory).

O.K. There are four ways that I know of to hold end mills in a
Bridgeport, and one of them is quite uncommon in the USA, though quite
common in the UK. I'll describe that one first:

1) Clarkson end mill holders:

The last few mm of the mill's shank is threaded, and threads
into collets which fit into the holder. The holder has a
projecting center which bears on the center hole of the end
mill.

I've got a couple of sizes of the holders, and none of the end
mills for the NTMB 40 spindle of my Nichols horizontal mill.

This style of holder has the advantage that the end mill cannot
shift its projection during cutting loads (unlike the R8
collets.

There are collets available for this to fit metric size shanks,
and fractional inch size shanks. The ones which I have are all
fractional inch sizes. I wish that I could buy the collets at
reasonable prices here in the USA -- just so I can try it at
least. :-)

2) Shrink-fit end mill holders:

Also uncommon -- except in serious production shops in the USA
(and perhaps elsewhere). The hole in the end mill holder is
just a little smaller than the diameter of the shank, so the
holder is heated and the end mill is inserted before the holder
can shrink again. I've never used one of these, but I have the
feeling that once an end mill is inserted, it is there for life.

And I don't know whether these have setscrews in addition to the
shrink fit or not.

3) Setscrew end mill holders:

The best bet in the USA where the Clarkson holders and end mills
are not readily available. The end mill is inserted, and the
flat-bottomed setscrew with a bevel edge is tightened. The
bevel on the end of the setscrew encounters a matching bevel at
the top end of the Weldon falt onto which the screw tightens.
This keeps the spiral of the end mill from pulling it down and
thus starting to cut deeper than you planned.

4) R8 collets:

The most common US way of holding end mills -- but the spiral of
the flutes can cause the end mill to walk down in the grip of
the collet during heavy cuts, resulting in damage to the
workpiece, and occasionally damage to the table or the vise as
well.

Note that R8 collets have a very small range of contraction, so
you can't mix metric collets and inch shanks or vice versa.

I've previously used the screw-shank variants so I'm comfortable with
them however I have no experience with the collets.

A few questions if I may:

a) Which method is better?

To my mind, the Clarkson system -- if that is one of what you
have. Your description was a little unclear to me.

Second would be the setscrew type of end mill holders, if you
can get end mills with Weldon flats.

Third (for convenience) would be the R8 collets -- but be
careful when taking heavy cuts.

Forth would be the shrink fit holders -- if only because a
hobby user can't usually afford to expend an end mill holder when an end
mill is no longer useful.

b) Dependant on a suitable diameter collet, do all "Plain shank" end
mills fit in the R8 collets?

Metric size end mill shanks fit the metric R8 collets (which it
appears you have). Fractional inch end mill shanks fit fractional inch
R8 collets. *Don't* try to stretch a collet to hold a larger size, it
will only lead to disaster.

c) When I purchase new end-mills, which of the above would you
recommend?

If you have the Clarkson holders, go that way. I don't know the
relative cost between Clarkson end mills, ones with Weldon flats, and
ones with purely cylindrical shanks, but if the cost of the Clarksons is
not prohibitive, it is more likely to prevent damage to a workpiece
which already has many hours of work invested in it.

While you are at it -- you also want 2-flute end mills for
cutting slots, and ones with more flutes (four and six are common in my
collection) for milling from the side.

There are also "roughing" end mills for fast material removal,
and the standard ones for everything else.

Good Luck,
DoN.

Hi Don,

Thanks for your information and encouraging comments!

I've noted your information regarding the flutes/roughing - very
helpful.

Thanks & kind regards,
Mike

MikeG wrote:
On Wed, 10 Dec 2008 12:53:19 +0000, David Billington
wrote:


MikeG wrote:

On Wed, 10 Dec 2008 11:42:53 +0000, David Billington
wrote:


snip


Hi David,

Many thanks for your detailed reply. I have noted your comments.

I've used the screw shank cutters and holder before but I didn't know
the correct name for them - thanks. Looking on the web, the autolock
inserts appear to be threaded but the ones supplied with my machine
aren't. They just slip into the holder and are held in place by the
retaining collar, tightened by a spanner. Is this still a "Clarkson
autolock"?


Mike,

I jumped to the conclusion you had a Clarkson autolock holder when
you said threaded shank cutters but was wrong by the sound of it. Have a
look here for some different collet types.
http://www.arceurotrade.co.uk/Catalogue/Collets . At a guess I might
think you have an ER collet holder as they don't have threads in them
and are quite common, see
http://www.arceurotrade.co.uk/Catalo...-Collet-Chucks .


The engineer who was showing me the ropes recommended that the screwed
end of the cutter protrude slightly (maybe 1mm+) from the end of the
holder before it was inserted into the sleeve and tightened. Is this
correct?


Sounds good.


I haven't managed to break anything yet and I'm keen to keep it that
way!


Always a good strategy.

Cheers,

Dave


Kind regards,
Mike





Hi Dave

Again, thanks for taking the time to reply.

I may have fed you a bum steer with my description of the collet - I
think it is a Clarkson Autolock - this is link to a picture.

http://www.mgarner.co.uk/Collet.jpg

Mike,

That's a Clarkson autolock style holder. I have one which is not
genuine Clarkson but had found no fault with it.

As an aside, please could you confirm that this is a "J" type head?

http://www.mgarner.co.uk/Bridgeport.jpg

That's a J head with 2 speed motor by the look of it. Have a look here
http://www.lathes.co.uk/bridgeport/ .

Cheers

Dave


Thanks & kind regards,
Mike

Should ER collets be a fifth?

* * * * Perhaps. *It depends on how much better they are at keeping the
cutters from creeping down under heavy cuts. *If they are the same, just
lump them with "R8"s with a higher cost added on. :-)

ER is not the only type of collet chuck, there's the Universal type
which looks similar but has fewer slots and doesn't have the groove
where the two angles meet (a Universal ZZ set came with my Index
mill). I believe there are other collet systems as well.
--Glenn Lyford

On 2008-12-12, MikeG wrote:
On Wed, 10 Dec 2008 12:53:19 +0000, David Billington
wrote:

[ ... ]

I jumped to the conclusion you had a Clarkson autolock holder when
you said threaded shank cutters but was wrong by the sound of it. Have a
look here for some different collet types.
http://www.arceurotrade.co.uk/Catalogue/Collets . At a guess I might
think you have an ER collet holder as they don't have threads in them
and are quite common, see
http://www.arceurotrade.co.uk/Catalo...-Collet-Chucks .

[ ... ]

Hi Dave

Again, thanks for taking the time to reply.

I may have fed you a bum steer with my description of the collet - I
think it is a Clarkson Autolock - this is link to a picture.

http://www.mgarner.co.uk/Collet.jpg

That certainly is -- or a clone if such are made. You will
probably find "CLARKSON" engraved in the edge of the nose-piece.

As an aside, please could you confirm that this is a "J" type head?

http://www.mgarner.co.uk/Bridgeport.jpg

I think that is a J-1 tyle -- the side covers say that it has
step pulleys. Look at the text stamped in the left-hand of the two
nameplates side by side. If it starts with a 'J', then you do have a
J-head. The '1' would be a 1 HP motor. Or maybe the serial number is
under the gray paint lower on the head.

Mine is a J-2 head made for a CNC machine (BOSS-3) so the feed
hardware is replaced with a ball screw surrounding the quill, and the
motor is hung from the underside of the casting instead of the upper
side, as well as mine having a variable speed crank in place of your
step pulleys.

If it has an R8 spindle, I don't think that it can be an M-head.
I think that they used Morse taper collets instead.

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 ---

Thanks for providing a picture of your disassembled Clarkson Autolock collet
parts, Mike.
I haven't seen them before, and I wouldn't have known what they were, if I
did see them.

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html


"MikeG" wrote in message
...

Hi Dave

Again, thanks for taking the time to reply.

I may have fed you a bum steer with my description of the collet - I
think it is a Clarkson Autolock - this is link to a picture.

http://www.mgarner.co.uk/Collet.jpg

As an aside, please could you confirm that this is a "J" type head?

http://www.mgarner.co.uk/Bridgeport.jpg

Thanks & kind regards,
Mike

On Fri, 12 Dec 2008 10:48:09 +0000, David Billington
wrote:

snip

I may have fed you a bum steer with my description of the collet - I
think it is a Clarkson Autolock - this is link to a picture.

http://www.mgarner.co.uk/Collet.jpg

Mike,

That's a Clarkson autolock style holder. I have one which is not
genuine Clarkson but had found no fault with it.

As an aside, please could you confirm that this is a "J" type head?

http://www.mgarner.co.uk/Bridgeport.jpg

That's a J head with 2 speed motor by the look of it. Have a look here
http://www.lathes.co.uk/bridgeport/ .

Cheers

Dave

Brilliant - thanks for the info, it's much appreciated.

Kind regards,
Mike

On 2008-12-13, Wild_Bill wrote:
Thanks for providing a picture of your disassembled Clarkson Autolock collet
parts, Mike.
I haven't seen them before, and I wouldn't have known what they were, if I
did see them.

What is not shown by the photos is that there is a thread on the
shank end of the end mill (just the last 3/16" or so) and a matching
thread on the bottom of the collet.

The center hole in the shank end of the edn mill engages the
center pin in the bottom of the holder's pocket, and when the nosepiece
is screwed in the taper inside the nose piece closes the outer end of
the collet to firmly center the end mill.

There is no way that a right-hand end mill can come out of the
holder with cutting forces. (Hmm ... I wonder whether there are
left-hand cutting end mills for the Clarkson system, and if so, whether
they have correspondingly threaded collets?) Anyone out there ever seen
left-hand end mills and collets for the Clarkson system?

BTW When I first started searching on eBay for Clarkson holders and
end mills I was driven nuts by constant hits on "American Idol"
DVDs. I had no idea why, never having wasted my time watching
that show, until I saw that they were featuring a "Kelly
Clarkson" as a singer. :-)

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 ---

Thanks for the additional details, DoN. As I looked at the parts I wondered
if this tooling could be used to drive a tap for tapping, or if the threaded
parts would just separate if the spindle was reversed.

But then, I don't know if it's even practical to tap threads with a
Bridgeport mill.

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html


"DoN. Nichols" wrote in message
...
On 2008-12-13, Wild_Bill wrote:
Thanks for providing a picture of your disassembled Clarkson Autolock
collet
parts, Mike.
I haven't seen them before, and I wouldn't have known what they were, if
I
did see them.

What is not shown by the photos is that there is a thread on the
shank end of the end mill (just the last 3/16" or so) and a matching
thread on the bottom of the collet.

The center hole in the shank end of the edn mill engages the
center pin in the bottom of the holder's pocket, and when the nosepiece
is screwed in the taper inside the nose piece closes the outer end of
the collet to firmly center the end mill.

There is no way that a right-hand end mill can come out of the
holder with cutting forces. (Hmm ... I wonder whether there are
left-hand cutting end mills for the Clarkson system, and if so, whether
they have correspondingly threaded collets?) Anyone out there ever seen
left-hand end mills and collets for the Clarkson system?

BTW When I first started searching on eBay for Clarkson holders and
end mills I was driven nuts by constant hits on "American Idol"
DVDs. I had no idea why, never having wasted my time watching
that show, until I saw that they were featuring a "Kelly
Clarkson" as a singer. :-)

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 2008-12-14, Wild_Bill wrote:
Thanks for the additional details, DoN. As I looked at the parts I wondered
if this tooling could be used to drive a tap for tapping, or if the threaded
parts would just separate if the spindle was reversed.

How would you deal with the needed feed per revolution? This is
mostly a CNC type job with a rigid tap holder. (After all, it takes a
lot of force to pull the spindle down with the tap threads, so it is
more likely to break the tap or strip out the starting threads.

But then, I don't know if it's even practical to tap threads with a
Bridgeport mill.

With a manual machine -- yes with the proper accessories.

Look at the various tapping heads (excluding the rigid ones). A
good example (and what I use in two sizes to tap even on a drill press)
are the ones made by TapMatic. It is a cylinder mounted between however
you drive it (I use a MT-2 shank in my drill press, or would use a
collet or a specially machined R8 or NTMB 30 or 40 shank on my mills)
and the special tap collet chuck which has Jacobs Rubberflex collet
(typically two sizes to cover the range for a given tap chuck) to hold
the tap concentric, and a pair of steel plates which clamp down on two
flats of the square at the back of the tap for driving it.

There is an arm protruding radially from the bottom of the
cylinder, which needs to contact some part of the machine to prevent the
whole outside of the cylinder from rotating.

The collet spindle has quite a bit of end play, and three
effective positions.

1) When the tap chuck is fully withdrawn, the chuck rotates at
the same speed as the drill press or milling machine spindle,
and allows a certain amount of motion to allow the tap to
self-feed a certain amount. Normally, you feed by hand at about
the speed that the tap feeds into the workpiece. (Use a gun
tap, of course, not a hand tap which needs frequent reversal.)

2) In the middle of the range, it disengages a dog clutch in the
housing, and allows the tap to stop while the spindle continues
to rotate. Normally, you set the depth stop on the machine to
stop it before you reach the end of the threads on the tap, or
before you reach the bottom of the hole on a blind hole.

3) When you start to withdraw the spindle, you engage a set of
planetary gears in the housing which starts the tap rotating
backwards at a somewhat higher speed than the spindle's forwards
direction.

With your other hand, you squirt a good tapping fluid on the tap
just before it enters the hole.

As I said above, I have two sizes of these TapMatic heads.

A) The smaller one goes from an 0-80 to a #10 or #12 -- and can
handle 1/4" in some materials. This one has an adjustable
torque limit clutch. You adjust it so it just barely does not
slip with a *new* tap and in the workpiece material which you
are using. When it starts to slip, it is time to replace the
tap, because it is getting too dull to trust in your workpiece.

B) The larger one will go up to 1/2" taps, and instead of the
torque limit, it has an adjustment of the free feed before the
dog clutch disengages. This is better when you are tapping near
the bottom of blind holes. Otherwise, you leave it with lots of
travel (1/8" or more, IIRC) when tapping through holes.

I believe that you can get both styles in both sizes, but when
getting things from eBay auctions and swap meets, you take what you can
get.

Some of them have a Jacobs taper in the back to accept your
choice of Morse taper arbor or whatever fits your machine.

Both of mine have a threaded hole instead, and I had to thread
No. 2 Morse Taper blanks to fit -- each has a different size of threaded
hole -- and the first one I got (the smaller one) had an adaptor with it
to fit a Turret drill press -- which is probably why I got it for such a
good price from eBay. :-)

There are other brands which are well thought of, but I can't
remember the names at the moment, since I don't have any examples. :-)

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 Sat, 13 Dec 2008 16:20:16 +0000, MikeG
wrote:

Be aware that the method of tightening a Clarkson collet is not in my
mind intuitive!
The correct way to fit a cutter is as follows
Screw the cutter into the collet a few turns. Insert the cutter and
collet into the nose piece. Screw the nose piece into the chuck body
until the mating flat faces touch. If the position of the cutter stops
this then unscrew the cutter until the nose piece can be screwed up to
touch. Screw the cutter up until it is solid. Tighten the nose piece
with a spanner.

Richard

On Fri, 12 Dec 2008 10:48:09 +0000, David Billington
wrote:

snip

I may have fed you a bum steer with my description of the collet - I
think it is a Clarkson Autolock - this is link to a picture.

http://www.mgarner.co.uk/Collet.jpg

Mike,

That's a Clarkson autolock style holder. I have one which is not
genuine Clarkson but had found no fault with it.

As an aside, please could you confirm that this is a "J" type head?

http://www.mgarner.co.uk/Bridgeport.jpg

That's a J head with 2 speed motor by the look of it. Have a look here
http://www.lathes.co.uk/bridgeport/ .

Cheers

Dave

Brilliant - thanks for the info, it's much appreciated.

Kind regards,
Mike
Richard

The only tapping under power that I've done has been on lathes, DoN. I
thought it might not be practical to tap on a Bridgeport with the tap
secured by a collet.

Most of the time, I tap by hand with a tap handle, or using a drill press
like a tapping fixture hith a hand crank (without using the motor) with the
taps held in the chuck.
No, not the slippy method, I've ground 3 flats on the shanks of a handfull
of taps for holding them in chucks.
A hub for the hand crank is permanently installed at the top of the DP
spindle and the crank fits in place by sticking the 2 protruding pins in the
crank handle into 2 holes in the hub (no screws or other fasteners
involved).
I can loosen the belt, disengage the quill return spring, and attach the
crank in about a minute.

If one were to use one of those shop-made telescoping tap holders for a
lathe tailstock, I suppose that the tap self-feeding itself wouldn't be an
issue whether it was used on a mill or drill press.. correct?

I've seen tapping heads like the TapMatic in catalogs and more recently in
videos, and have read numerous RCM posts about how slick they are. I've read
a lot here in RCM, and when contributors like yourself, and at least several
others, take the time to write detailed commentaries about metalworking
topics, I always take the time to read them.

As I've stated before, anyone that spends any significant time "on RCM"
would be doing themselves a great disservice if they aren't reading all the
really good comments concerning all the widely varied metalworking topics.

Some folks like to read a morning paper.. I read RCM instead, nearly every
day, maybe missing a couple per month.

Fortunately, most of the contributors of the metal related content are
talented at describing their thoughts well in text.
Perhaps most fortunately, those frequent contributors have been willing to
stick around to continue sharing their experience(s) and helping others,
despite all the non-metal noise that takes place regularly.

The anniversary of the loss of one of the great RCM contributors will be
remembered/observed soon.. RIP Tnut

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html


"DoN. Nichols" wrote in message
...
On 2008-12-14, Wild_Bill wrote:
Thanks for the additional details, DoN. As I looked at the parts I
wondered
if this tooling could be used to drive a tap for tapping, or if the
threaded
parts would just separate if the spindle was reversed.

How would you deal with the needed feed per revolution? This is
mostly a CNC type job with a rigid tap holder. (After all, it takes a
lot of force to pull the spindle down with the tap threads, so it is
more likely to break the tap or strip out the starting threads.

But then, I don't know if it's even practical to tap threads with a
Bridgeport mill.

With a manual machine -- yes with the proper accessories.

Look at the various tapping heads (excluding the rigid ones). A
good example (and what I use in two sizes to tap even on a drill press)
are the ones made by TapMatic. It is a cylinder mounted between however
you drive it (I use a MT-2 shank in my drill press, or would use a
collet or a specially machined R8 or NTMB 30 or 40 shank on my mills)
and the special tap collet chuck which has Jacobs Rubberflex collet
(typically two sizes to cover the range for a given tap chuck) to hold
the tap concentric, and a pair of steel plates which clamp down on two
flats of the square at the back of the tap for driving it.

There is an arm protruding radially from the bottom of the
cylinder, which needs to contact some part of the machine to prevent the
whole outside of the cylinder from rotating.

The collet spindle has quite a bit of end play, and three
effective positions.

1) When the tap chuck is fully withdrawn, the chuck rotates at
the same speed as the drill press or milling machine spindle,
and allows a certain amount of motion to allow the tap to
self-feed a certain amount. Normally, you feed by hand at about
the speed that the tap feeds into the workpiece. (Use a gun
tap, of course, not a hand tap which needs frequent reversal.)

2) In the middle of the range, it disengages a dog clutch in the
housing, and allows the tap to stop while the spindle continues
to rotate. Normally, you set the depth stop on the machine to
stop it before you reach the end of the threads on the tap, or
before you reach the bottom of the hole on a blind hole.

3) When you start to withdraw the spindle, you engage a set of
planetary gears in the housing which starts the tap rotating
backwards at a somewhat higher speed than the spindle's forwards
direction.

With your other hand, you squirt a good tapping fluid on the tap
just before it enters the hole.

As I said above, I have two sizes of these TapMatic heads.

A) The smaller one goes from an 0-80 to a #10 or #12 -- and can
handle 1/4" in some materials. This one has an adjustable
torque limit clutch. You adjust it so it just barely does not
slip with a *new* tap and in the workpiece material which you
are using. When it starts to slip, it is time to replace the
tap, because it is getting too dull to trust in your workpiece.

B) The larger one will go up to 1/2" taps, and instead of the
torque limit, it has an adjustment of the free feed before the
dog clutch disengages. This is better when you are tapping near
the bottom of blind holes. Otherwise, you leave it with lots of
travel (1/8" or more, IIRC) when tapping through holes.

I believe that you can get both styles in both sizes, but when
getting things from eBay auctions and swap meets, you take what you can
get.

Some of them have a Jacobs taper in the back to accept your
choice of Morse taper arbor or whatever fits your machine.

Both of mine have a threaded hole instead, and I had to thread
No. 2 Morse Taper blanks to fit -- each has a different size of threaded
hole -- and the first one I got (the smaller one) had an adaptor with it
to fit a Turret drill press -- which is probably why I got it for such a
good price from eBay. :-)

There are other brands which are well thought of, but I can't
remember the names at the moment, since I don't have any examples. :-)

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 ---

Richard Edwards wrote:
On Sat, 13 Dec 2008 16:20:16 +0000, MikeG
wrote:

Be aware that the method of tightening a Clarkson collet is not in my
mind intuitive!
The correct way to fit a cutter is as follows
Screw the cutter into the collet a few turns. Insert the cutter and
collet into the nose piece. Screw the nose piece into the chuck body
until the mating flat faces touch. If the position of the cutter stops
this then unscrew the cutter until the nose piece can be screwed up to
touch. Screw the cutter up until it is solid. Tighten the nose piece
with a spanner.

Richard


I was taught to leave a slight gap between the body and closer, screw
the cutter in till it bottoms, then tighten the closer. This still
leaves a slight gap but holds the cutter hard against the centre post.

On Fri, 12 Dec 2008 10:48:09 +0000, David Billington
wrote:

snip


I may have fed you a bum steer with my description of the collet - I
think it is a Clarkson Autolock - this is link to a picture.

http://www.mgarner.co.uk/Collet.jpg


Mike,

That's a Clarkson autolock style holder. I have one which is not
genuine Clarkson but had found no fault with it.


As an aside, please could you confirm that this is a "J" type head?

http://www.mgarner.co.uk/Bridgeport.jpg


That's a J head with 2 speed motor by the look of it. Have a look here
http://www.lathes.co.uk/bridgeport/ .

Cheers

Dave

Brilliant - thanks for the info, it's much appreciated.

Kind regards,
Mike

Richard

Richard Edwards wrote:
On Sat, 13 Dec 2008 16:20:16 +0000, MikeG
wrote:

Be aware that the method of tightening a Clarkson collet is not in my
mind intuitive!
The correct way to fit a cutter is as follows
Screw the cutter into the collet a few turns. Insert the cutter and
collet into the nose piece. Screw the nose piece into the chuck body
until the mating flat faces touch. If the position of the cutter stops
this then unscrew the cutter until the nose piece can be screwed up to
touch. Screw the cutter up until it is solid. Tighten the nose piece
with a spanner.

Richard


Richard,

It seems I was taught incorrectly how to use a Clarkson autolock
holder and you above post is the correct technique. A quick google
turned up the following which I shall try the next time I use it.

http://www.denfordata.com/bb/viewtop...1bd3b 1810519

Cheers

Dave


On Fri, 12 Dec 2008 10:48:09 +0000, David Billington
wrote:

snip


I may have fed you a bum steer with my description of the collet - I
think it is a Clarkson Autolock - this is link to a picture.

http://www.mgarner.co.uk/Collet.jpg


Mike,

That's a Clarkson autolock style holder. I have one which is not
genuine Clarkson but had found no fault with it.


As an aside, please could you confirm that this is a "J" type head?

http://www.mgarner.co.uk/Bridgeport.jpg


That's a J head with 2 speed motor by the look of it. Have a look here
http://www.lathes.co.uk/bridgeport/ .

Cheers

Dave

Brilliant - thanks for the info, it's much appreciated.

Kind regards,
Mike

Richard

On 2008-12-14, Wild_Bill wrote:
The only tapping under power that I've done has been on lathes, DoN. I
thought it might not be practical to tap on a Bridgeport with the tap
secured by a collet.

Not just secured by a collet -- but you might be able to use a
releasing tap holder (made to be used in late turrets and in automatic
screw machines) as long as you carefully set the depth stop based on
where the dog clutch releases so you don't drive down into the bottom of
the hole and break the tap off in the workpiece. :-)

Most of the time, I tap by hand with a tap handle, or using a drill press
like a tapping fixture hith a hand crank (without using the motor) with the
taps held in the chuck.
No, not the slippy method, I've ground 3 flats on the shanks of a handfull
of taps for holding them in chucks.

O.K. You know that there is a keyless chuck by Albrecht which
has diamond dust impregnated jaws, so it *can* grip a tap or a mill
without slipping. And -- there are versions of the Albrecht chucks
which are designed to lock as well. Both features are only found on
quite expensive Albrechts -- usually with R8 shanks instead of a female
Jacobs taper to allow interchangeable arbors.

A hub for the hand crank is permanently installed at the top of the DP
spindle and the crank fits in place by sticking the 2 protruding pins in the
crank handle into 2 holes in the hub (no screws or other fasteners
involved).
I can loosen the belt, disengage the quill return spring, and attach the
crank in about a minute.

Nice. I think that the quill return spring on mine would be the
slowest to disengage and reset later.

If one were to use one of those shop-made telescoping tap holders for a
lathe tailstock, I suppose that the tap self-feeding itself wouldn't be an
issue whether it was used on a mill or drill press.. correct?

The telescoping ones which I have seen have been designed to
slide on a rod held by the tailstock, and to be prevented from turning
by gripping either a knurled surface or a short T-handle. When the tap
reaches the proper depth, you release the handle and let it spin.

But the releasing tap holders (commercial product for older
turret lathes and for automatic screw machines) could be used in a mill.
You stop feeding and the threads draw the tap down just a little more to
disengage the dog clutch. Then you stop the spindle, reverse it, and
pull up (many are designed with a directional dog clutch, so it will
hold in reverse even though it has released in forward.

I'm familiar with these because I have a bed turret (replaces
the tailstock) for my 12x24" Clausing, and I use it form time to time
with turret tooling acquired from eBay auctions.

I've seen tapping heads like the TapMatic in catalogs and more recently in
videos, and have read numerous RCM posts about how slick they are.

Generally, if I have more than two or three holes to tap (and
I'm not on the lathe) I'll use the tapping head. Particularly nice when
I had to tap about 30 1/4-20 holes in 3/16" thick steel to make a new
apron for the 24" DiAcro shear which I got last year. Any manual method
of tapping that many holes that large in steel gets old fast. :-)

I've read
a lot here in RCM, and when contributors like yourself, and at least several
others, take the time to write detailed commentaries about metalworking
topics, I always take the time to read them.

[ ... ]

Fortunately, most of the contributors of the metal related content are
talented at describing their thoughts well in text.

Most of us like sharing what we have learned -- to save others
the time which we spent the hard way. :-)

Perhaps most fortunately, those frequent contributors have been willing to
stick around to continue sharing their experience(s) and helping others,
despite all the non-metal noise that takes place regularly.

Well ... as an example, my killfile zapped about 2/3 of the
articles. It was worse prior to the election - 3/4 was being zapped at
a time. :-)

If you chase down a version of slrn for your system (I believe
that it is available for Windows as well as unix/linux systems and Macs),
and drop me an e-mail, I can send you my current killfile to give you a
quick start. (I'll strip out the parts which apply to other
newsgroups.) Among other things, I have a lot of blocking by IP range
to keep the Chinese shoe knockoff vendors out of my newsreader, and the
various Indian scams.

The anniversary of the loss of one of the great RCM contributors will be
remembered/observed soon.. RIP Tnut

(Hmm ... were you posting under a different name back then?)

Indeed so.
He is still missed.
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 2008-12-14, Richard Edwards wrote:
On Sat, 13 Dec 2008 16:20:16 +0000, MikeG
wrote:

Be aware that the method of tightening a Clarkson collet is not in my
mind intuitive!
The correct way to fit a cutter is as follows
Screw the cutter into the collet a few turns. Insert the cutter and
collet into the nose piece. Screw the nose piece into the chuck body
until the mating flat faces touch. If the position of the cutter stops
this then unscrew the cutter until the nose piece can be screwed up to
touch. Screw the cutter up until it is solid. Tighten the nose piece
with a spanner.

Thanks. I had not known that. If I ever get a set of mills to
match my holders, I'll have to remember that.

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 ---

I was thinking that I had seen some of the telescoping shop-made tap
guide/holders for lathe tailstocks that had a key or pin to keep the tap
from turning, but allow the tap to self-feed into the rotating part.
Stopping the spindle would then be the method to stop the feeding.

I suppose if I happened to stumble upon a tapping setup with the dog clutch,
I'd be inclined to buy it because they sound versatile.

Oh, the other tapping with power that I've done has been #6-8-10 taps in
steel panels for mounting relays and controls.. works a treat for lots of
thru-holes.
I wouldn't wanna try it with a non-reversing drill motor though.

I was aware the diamond dust filled jaw chucks existed, but don't think I've
ever paid much attention to the pricing.
I just got a nice, used, 3-piece set of TRW USA tap handles with the opposed
handles, and a moving jaw that closes on the square section of taps, but
like you said, hand tapping a lot of holes gets old fast.

When I was lurking and just observing RCM interactions/frictions, Tnut,
Fitch, Albrecht and numerous others were regulars.
When I started posting in RCM I was probably with the ISP tcis or usachoice,
then Goog, and Teranews briefly, using the moniker kwag98 initially, then
others similar to the present one, as WB was my sig for a number of years of
posting in sci.electronics.repair.

The non-metalworking posts don't cause much aggravation for me, as I can
just ignore them, since most of them generally, and the participants'
opinions on those topics, aren't of any more interest to me than the spam
sales messages.

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html


"DoN. Nichols" wrote in message
...
On 2008-12-14, Wild_Bill wrote:
The only tapping under power that I've done has been on lathes, DoN. I
thought it might not be practical to tap on a Bridgeport with the tap
secured by a collet.

Not just secured by a collet -- but you might be able to use a
releasing tap holder (made to be used in late turrets and in automatic
screw machines) as long as you carefully set the depth stop based on
where the dog clutch releases so you don't drive down into the bottom of
the hole and break the tap off in the workpiece. :-)

Most of the time, I tap by hand with a tap handle, or using a drill press
like a tapping fixture hith a hand crank (without using the motor) with
the
taps held in the chuck.
No, not the slippy method, I've ground 3 flats on the shanks of a
handfull
of taps for holding them in chucks.

O.K. You know that there is a keyless chuck by Albrecht which
has diamond dust impregnated jaws, so it *can* grip a tap or a mill
without slipping. And -- there are versions of the Albrecht chucks
which are designed to lock as well. Both features are only found on
quite expensive Albrechts -- usually with R8 shanks instead of a female
Jacobs taper to allow interchangeable arbors.

A hub for the hand crank is permanently installed at the top of the DP
spindle and the crank fits in place by sticking the 2 protruding pins in
the
crank handle into 2 holes in the hub (no screws or other fasteners
involved).
I can loosen the belt, disengage the quill return spring, and attach the
crank in about a minute.

Nice. I think that the quill return spring on mine would be the
slowest to disengage and reset later.

If one were to use one of those shop-made telescoping tap holders for a
lathe tailstock, I suppose that the tap self-feeding itself wouldn't be
an
issue whether it was used on a mill or drill press.. correct?

The telescoping ones which I have seen have been designed to
slide on a rod held by the tailstock, and to be prevented from turning
by gripping either a knurled surface or a short T-handle. When the tap
reaches the proper depth, you release the handle and let it spin.

But the releasing tap holders (commercial product for older
turret lathes and for automatic screw machines) could be used in a mill.
You stop feeding and the threads draw the tap down just a little more to
disengage the dog clutch. Then you stop the spindle, reverse it, and
pull up (many are designed with a directional dog clutch, so it will
hold in reverse even though it has released in forward.

I'm familiar with these because I have a bed turret (replaces
the tailstock) for my 12x24" Clausing, and I use it form time to time
with turret tooling acquired from eBay auctions.

I've seen tapping heads like the TapMatic in catalogs and more recently
in
videos, and have read numerous RCM posts about how slick they are.

Generally, if I have more than two or three holes to tap (and
I'm not on the lathe) I'll use the tapping head. Particularly nice when
I had to tap about 30 1/4-20 holes in 3/16" thick steel to make a new
apron for the 24" DiAcro shear which I got last year. Any manual method
of tapping that many holes that large in steel gets old fast. :-)

I've
read
a lot here in RCM, and when contributors like yourself, and at least
several
others, take the time to write detailed commentaries about metalworking
topics, I always take the time to read them.

[ ... ]

Fortunately, most of the contributors of the metal related content are
talented at describing their thoughts well in text.

Most of us like sharing what we have learned -- to save others
the time which we spent the hard way. :-)

Perhaps most fortunately, those frequent contributors have been willing
to
stick around to continue sharing their experience(s) and helping others,
despite all the non-metal noise that takes place regularly.

Well ... as an example, my killfile zapped about 2/3 of the
articles. It was worse prior to the election - 3/4 was being zapped at
a time. :-)

If you chase down a version of slrn for your system (I believe
that it is available for Windows as well as unix/linux systems and Macs),
and drop me an e-mail, I can send you my current killfile to give you a
quick start. (I'll strip out the parts which apply to other
newsgroups.) Among other things, I have a lot of blocking by IP range
to keep the Chinese shoe knockoff vendors out of my newsreader, and the
various Indian scams.

The anniversary of the loss of one of the great RCM contributors will be
remembered/observed soon.. RIP Tnut

(Hmm ... were you posting under a different name back then?)

Indeed so.
He is still missed.
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 Mon, 15 Dec 2008 11:56:48 -0500, "Wild_Bill"
wrote:

I was thinking that I had seen some of the telescoping shop-made tap
guide/holders for lathe tailstocks that had a key or pin to keep the tap
from turning, but allow the tap to self-feed into the rotating part.
Stopping the spindle would then be the method to stop the feeding.

Hey WB,

Most of those tailstock tap accessories have two slots opposite one
another in the carrier of a size to allow a T-tap handle to slide into
it. In operation, the "depth of threading" is set by advancing or
retracting the tailstock and barrel to set a point of release for the
T-handle, which allows the T-handle to just spin when it reaches the
preset depth by moving/being pulled out of the slots so it is no
longer held by the tailstock carrier.

Take care.

Brian Lawson,
Bothwell, Ontario..

On 2008-12-15, Wild_Bill wrote:
I was thinking that I had seen some of the telescoping shop-made tap
guide/holders for lathe tailstocks that had a key or pin to keep the tap
from turning, but allow the tap to self-feed into the rotating part.
Stopping the spindle would then be the method to stop the feeding.

That sounds a little hazardous -- if your reaction itme is poor,
or if you switch through "STOP" to "REV" and your lathe happens to have
a single-phase cap-start motor, it will keep going forward and bury the
remains of the tap in the workpiece. :-)

Now -- if the key is not full length, and you position your stop
properly so when the tap reaches the needed depth, it pulls clear of the
key and starts to free rotate, you have an approximation of the dog
clutch, and you can use it safely.

I suppose if I happened to stumble upon a tapping setup with the dog clutch,
I'd be inclined to buy it because they sound versatile.

They are better with a turret (bed or otherwise) with individual
stops for each station, and lever feed (four levers like a turnstile) so
you can feed at a reasonable speed until you reach the stop. The total
travel of the dog clutch is on the order of 1/8" or 3/16" typically, so
trying to keep up with it with the hand crank on a standard tailstock is
awkward.

A lever feed tailstock would work well.

Or -- mount it on a boring bar holder and set up a turret bed
stop with one station to stop the carriage at the right point for the
tap. For that matter, you could use the same setup with other turret
tools like "roller box tools" (turn to diameter in a single pass with a
set of roller steadys associated with the cutter), or Geometric die
heads (there are other brands more common in the UK) for threading to
depth at speed, and which release by letting the chasers (like 4-jaw
chuck jaws) spring outwards at the end of the thread -- so you don't
even nave to reverse the spindle to pull it off, because the threads are
disengaged.

For that matter, there are Geometric "Collapsiing taps" which
are like a Geometric die head turned inside out. Probably start around
1" ID, and increase in size to whatever limit the size of your lathe may
impose. My bed turret has 1" shank holes in the stations. I've got a
couple of the collapsing tap setups -- but I am limited to the chasers
which came with them -- I don't seem to see the chasers very often on
eBay.

Also -- there are T-bar knurling tools which are fed on over
the end of the workpiece with the knurling rollers on two shafts which
come in from opposite sides of the workpiece for balanced loads on the
machine.

All of these on a quick-change toolpost with boring bar holders
would require carefully setting the cross-feed and the height adjustment
properly before starting, while the turret is always on center. But
once set up, if all of your boring bar holders had the same offset from
dovetail to center of the bore, then you could change tools and change
a turret type carriage stop to use them almost as easily as you do the
turret -- except that you have to be careful to keep them in the right
order and matching the turret bed stop.

Oh, the other tapping with power that I've done has been #6-8-10 taps in
steel panels for mounting relays and controls.. works a treat for lots of
thru-holes.
I wouldn't wanna try it with a non-reversing drill motor though.

Agreed. I've done that with gun taps in that range -- with 6-32
being the one most likely to lead to disaster. It is just too weak a
thread thanks to the coarseness of the thread vs the small OD leading to
a very small root diameter. :-)

You know -- a non-reversible electric drill could be fitted with
a stop for the radial arm on a TapMatic head and that could be used by
hand with reasonable care -- up to significantly larger taps if you have
a hefty enough drill motor, and perhaps a helper to keep it from
twisting. :-)

I was aware the diamond dust filled jaw chucks existed, but don't think I've
ever paid much attention to the pricing.

Since these come only with the permanent R8 or NTMB 30 or 40 type
shanks, they tend to be quite expensive.

I guess that you could get replacement jaws for one and fit them
to a standard one -- if you did not need the locking feature as well. :-)

I just got a nice, used, 3-piece set of TRW USA tap handles with the opposed
handles, and a moving jaw that closes on the square section of taps, but
like you said, hand tapping a lot of holes gets old fast.

Hmm ... just the match for my set of TRW taps and dies (staring,
plug, and finishing) from 0-80 to 1-8. Big flat metal case with fitted
plastic foam liner. I bid on it on eBay many years ago in an auction
where there were no photos. I think that others skipped it for that
reason. I forget what I paid for the set -- but I think that it was
about $100.00. The taps and dies showed no sign of every having been
used. :-)

When I was lurking and just observing RCM interactions/frictions, Tnut,
Fitch, Albrecht and numerous others were regulars.

Yep -- I wish that Fitch would return, since his move is
complete. And I would like to see Pete Albrecht back, too.

When I started posting in RCM I was probably with the ISP tcis or usachoice,
then Goog, and Teranews briefly, using the moniker kwag98 initially, then
others similar to the present one, as WB was my sig for a number of years of
posting in sci.electronics.repair.

O.K. So you were lurking back in those days -- and the username
was switching as well. And I tend to notice the username more than the
real name.

I've had the same username since about 1985 or so, when I set up
my first unix box and got a uucp feed for it from uunet. I got my
domain at the same time.

The non-metalworking posts don't cause much aggravation for me, as I can
just ignore them, since most of them generally, and the participants'
opinions on those topics, aren't of any more interest to me than the spam
sales messages.

The killfiles save me the trouble of identifying a lot of them,
and off-topic threads which start I usually add the "Subject: " to the
killfile with a 30 or 60 day fuse before it is turned off. Otherwise
the killfile would get so big that it would take forever to process. :-)

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 16 Dec 2008 02:46:51 GMT, "DoN. Nichols"
wrote:


Oh, the other tapping with power that I've done has been #6-8-10 taps in
steel panels for mounting relays and controls.. works a treat for lots of
thru-holes.
I wouldn't wanna try it with a non-reversing drill motor though.


You know -- a non-reversible electric drill could be fitted with
a stop for the radial arm on a TapMatic head and that could be used by
hand with reasonable care -- up to significantly larger taps if you have
a hefty enough drill motor, and perhaps a helper to keep it from
twisting. :-)


See McMaster p/n 2559A14. I've got one that came in auction lot, but
don't find it very useful. Gripping the lower half of the housing
takes the place of the torque arm on a normal tapping head. Your
comment that a helper would be nice is on the money. If you're driving
a tap that's large enough that the gearing might be an advantage, it's
hard holding on tight enough to stop the housing's rotation.

--
Ned Simmons

On 2008-12-16, Ned Simmons wrote:
On 16 Dec 2008 02:46:51 GMT, "DoN. Nichols"
wrote:


Oh, the other tapping with power that I've done has been #6-8-10 taps in
steel panels for mounting relays and controls.. works a treat for lots of
thru-holes.
I wouldn't wanna try it with a non-reversing drill motor though.


You know -- a non-reversible electric drill could be fitted with
a stop for the radial arm on a TapMatic head and that could be used by
hand with reasonable care -- up to significantly larger taps if you have
a hefty enough drill motor, and perhaps a helper to keep it from
twisting. :-)


See McMaster p/n 2559A14. I've got one that came in auction lot, but
don't find it very useful. Gripping the lower half of the housing
takes the place of the torque arm on a normal tapping head.

That explains why is is so limited on tap sizes. The TapMatic
warns you to not try to hold the arm by hand, so it probably has a lot
more torque to deal with.

Your
comment that a helper would be nice is on the money. If you're driving
a tap that's large enough that the gearing might be an advantage, it's
hard holding on tight enough to stop the housing's rotation.

And that is without the tapping adaptor's housing being locked
to the drill motor's housing. With that, you have that adding to the
torque that the tap creates under load.

It might be fun to try it once -- but not at that price. :-)

If I get a drill motor with a cylindrical bearing housing,
perhaps I'll make a clamp-on sleeve to hold a pin for the torque arm so
I don't have to play with holding the bottom housing too.

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 Dec 16, 9:42*pm, "DoN. Nichols" wrote:
On 2008-12-16, Ned Simmons wrote:





On 16 Dec 2008 02:46:51 GMT, "DoN. Nichols"
wrote:

Oh, the other tapping with power that I've done has been #6-8-10 taps in
steel panels for mounting relays and controls.. works a treat for lots of
thru-holes.
I wouldn't wanna try it with a non-reversing drill motor though.

* * * *You know -- a non-reversible electric drill could be fitted with
a stop for the radial arm on a TapMatic head and that could be used by
hand with reasonable care -- up to significantly larger taps if you have
a hefty enough drill motor, and perhaps a helper to keep it from
twisting. :-)

See McMaster p/n 2559A14. I've got one that came in auction lot, but
don't find it very useful. Gripping the lower half of the housing
takes the place of the torque arm on a normal tapping head.

* * * * That explains why is is so limited on tap sizes. *The TapMatic
warns you to not try to hold the arm by hand, so it probably has a lot
more torque to deal with.

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Your
comment that a helper would be nice is on the money. If you're driving
a tap that's large enough that the gearing might be an advantage, it's
hard holding on tight enough to stop the housing's rotation.

* * * * And that is without the tapping adaptor's housing being locked
to the drill motor's housing. *With that, you have that adding to the
torque that the tap creates under load.

* * * * It might be fun to try it once -- but not at that price. :-)

* * * * If I get a drill motor with a cylindrical bearing housing,
perhaps I'll make a clamp-on sleeve to hold a pin for the torque arm so
I don't have to play with holding the bottom housing too.

* * * * 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 ---- Hide quoted text -

- Show quoted text -

Gentlemen. This seems like an appropriate thread to inquire about an
equipment item I recently bought. It is a Dumore automatic drilling/
tapping machine. I bought it at an auction because there were no
other bids. Apparently, it is a pretty expensive tool but I still
don't understand exactly what it is.

However, after going to the Dumore site they describe it (although not
in these exact words) as an automated drill press for dummies. I will
give the model number later since I don't remember it now. But
apparently, by changing pulleys, the speed can be cranked up to 7500
rpm. It is air controlled and the plunging operations can be
programmed and are repeatable to .0001 accuracy or something like
that. I think they call it an "automatic drilling machine".

Anybody know what I'm talking about and have any experience with
these? I thought I might try to sell it on ebay.

Regards,
Vernon

"Vernon" wrote in message
...
On Dec 16, 9:42 pm, "DoN. Nichols" wrote:
On 2008-12-16, Ned Simmons wrote:

Gentlemen. This seems like an appropriate thread to inquire about an
equipment item I recently bought. It is a Dumore automatic drilling/
tapping machine. I bought it at an auction because there were no
other bids. Apparently, it is a pretty expensive tool but I still
don't understand exactly what it is.

However, after going to the Dumore site they describe it (although not
in these exact words) as an automated drill press for dummies. I will
give the model number later since I don't remember it now. But
apparently, by changing pulleys, the speed can be cranked up to 7500
rpm. It is air controlled and the plunging operations can be
programmed and are repeatable to .0001 accuracy or something like
that. I think they call it an "automatic drilling machine".

Anybody know what I'm talking about and have any experience with
these? I thought I might try to sell it on ebay.

Regards,
Vernon

Sounds a lot like a Snow tapper that I tried to give away on this NG earlier
this year - ultimately we took it apart for scrap, saving some solenoids and
motors - and a little hardware. The tool worked perfectly, but no one uses
these any more. Basically you set it up (speeds, depth, force down, force
up), put your part in and step on a foot switch, it does the rest.



** Posted from http://www.teranews.com **

On 2008-12-17, Vernon wrote:

[ ... ]

Gentlemen. This seems like an appropriate thread to inquire about an
equipment item I recently bought. It is a Dumore automatic drilling/
tapping machine. I bought it at an auction because there were no
other bids. Apparently, it is a pretty expensive tool but I still
don't understand exactly what it is.

However, after going to the Dumore site they describe it (although not
in these exact words) as an automated drill press for dummies. I will
give the model number later since I don't remember it now. But
apparently, by changing pulleys, the speed can be cranked up to 7500
rpm. It is air controlled and the plunging operations can be
programmed and are repeatable to .0001 accuracy or something like
that. I think they call it an "automatic drilling machine".

If it is for tapping as well, it should also have provisions for
a precise feed per revolution, so it will feed that tap at the thread
rate.

It would be excellent for the job which the original poster is
doing -- *if* it has the necessary feed gears for the 32 TPI which he is
tapping. (Hmm ... I wonder whether this one might have a floating tap
chuck which senses when the tap tries to get ahead and provides more
feed to keep up?)

Anybody know what I'm talking about and have any experience with
these? I thought I might try to sell it on ebay.

It sounds like a lovely toy when you have a lot of the same
thread to tap. If it needs change gears to set up the feed for a given
thread pitch, then it could be expansive to change to a different
pitch.

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 17 Dec 2008 03:42:47 GMT, "DoN. Nichols"
wrote:


It might be fun to try it once -- but not at that price. :-)

I'll let you try mine all you want for considerably less than
McMaster's price. g Seriously, for smaller taps I find a drill with
a convenient reversing switch much more useful, like the older
Milwaukees with a flipper right above the trigger.
http://www.cityelectricmotor.com/ky/...ges/M02226.gif


If I get a drill motor with a cylindrical bearing housing,
perhaps I'll make a clamp-on sleeve to hold a pin for the torque arm so
I don't have to play with holding the bottom housing too.

You got me excited for a minute there thinking I could do something
similar with my attachment. I have a 1/2" drill that has a cylindrical
boss behind the chuck where the cross handle clamps. Unfortunately, I
forgot that you restrain the bottom half of the housing to go forward,
and the top to reverse.

--
Ned Simmons

Thanks Brian, I see what you described, similar to those sockets for turning
wingnuts.

I think I've seen some tap holders that didn't release, instead, the user
just stops the spindle motor.
I dunno what speeds most home shop operators are tapping at, but I run 'em
slow.
If shutting the motor off to stop threading near a shoulder is successful
(for me it is), then stopping at a thread depth with a tap isn't a big
problem.
I've put masking tape on the tap for a depth indicator, when I've used a tap
in a tailstock chuck, with the tailstock lockdown bolt slightly loose.

Nothing disasterous happened with the above method, and I was tapping 3/8-24
NF threads in 316 stainless steel. Slow speed, cutting lubricant and a high
quality tap.

Those parts were adapters for desoldering irons, to allow common 1/8"
desoldering tips to be used with an Ungar desoldering iron that utilized
essentially unique tips that were machined from 7/16" diameter steel stock,
then plated.
The adapters allowed the users to swap out much less expensive tips with a
set screw in the adapter body. BTW, the set screw was #6-32, but hand
tapped.

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html


"Brian Lawson" wrote in message
...
On Mon, 15 Dec 2008 11:56:48 -0500, "Wild_Bill"
wrote:

I was thinking that I had seen some of the telescoping shop-made tap
guide/holders for lathe tailstocks that had a key or pin to keep the tap
from turning, but allow the tap to self-feed into the rotating part.
Stopping the spindle would then be the method to stop the feeding.

Hey WB,

Most of those tailstock tap accessories have two slots opposite one
another in the carrier of a size to allow a T-tap handle to slide into
it. In operation, the "depth of threading" is set by advancing or
retracting the tailstock and barrel to set a point of release for the
T-handle, which allows the T-handle to just spin when it reaches the
preset depth by moving/being pulled out of the slots so it is no
longer held by the tailstock carrier.

Take care.

Brian Lawson,
Bothwell, Ontario..