Re: [Emc-users] Where are you getting R8 square collets for driving taps?

[Marcus Bowman]

On 7 Mar 2018, at 06:28, Erik Christiansen wrote:

> On 07.03.18 00:58, Gene Heskett wrote:
>> And the grub screws stayed tight?
> 

I made a whole tapping system for my pillar tool, for small taps, using the 
4-grubscrew technique, and I have used it successfully for years. I only use it 
for threads below M3, though, and only for manual tapping. One flaw is that 
although the grubscrews stay fairly tight, most of the time, they do have a 
tendency to work loose because of the angle of the twisting force, which is 
roughly parallel to the flat of the squares, at the tangent point of the 
imaginary same-diameter circle.
Another more annoying problem is that there is nothing much to stop the tap 
from tending to slip along its long axis, as the screws slacken slightly. What 
they need is a conical hole, a vee or a flat with shoulders ground into the 
shank, to stop the sliding.
For larger taps, that would be easier to arrange, but I suspect the forces 
involved with those larger taps would tend to magnify the problems.

Is the answer not to use a thread mill? Expensive - yes - but more controllable 
and easier to cut the thread in several passes, I think. I've no experience, 
except of looking at my shockingly expensive thread mill cutter and wondering 
about its life expectancy.


Marcus


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Re: [Emc-users] Where are you getting R8 square collets for driving taps?

[Erik Christiansen]

On 07.03.18 00:58, Gene Heskett wrote:
> And the grub screws stayed tight?

Yup, but that was only hand tapping. A bit of Loctite would be good
insurance when rigid tapping.

> The die holder I'd have to make as all mine are handled for 2 handed
> use.

The die holder was only needed because I made do with manual tapping,
just using the drill bit in the back for aligning the tap vertically,
and winding by hand.

With the 1/2" round held in a collet, there's no need for a die holder.
On encountering your difficulties, though, I think I'd make one up in
the diameter of the largest ER40 collet I have, to maximise grip
diameter and area, then make sure there's no oil on collet or tap holder
before they go in.

> Ignore that grinding noise, its just me thinking. Send me a PM with a
> couple pix if you can.

Went around the workshop with my glasses on, but the little critters
didn't come when called - hold on, there's a couple of pics from when I
made 'em. Will send.

Erik

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Re: [Emc-users] Where are you getting R8 square collets for driving taps?

[Gene Heskett]

On Wednesday 07 March 2018 00:29:43 Erik Christiansen wrote:

> On 06.03.18 23:05, Gene Heskett wrote:
> > It appears that its well nigh impossible to get a firm enough grip
> > on a tap shank, and on the smooth, unkeyed TTS ER-32 holder, to
> > reliably lock a tap for rigid tapping.  I've considered buying
> > ER-32's with square sockets, but for >8mm taps, the TTS
> > adapter/holder will spin in the R8.
>
> The only thing I could suggest is the guts of some "tap-hats" I made -
> that's just a length of 1/2" round drilled/bored to take the tap
> shank, and cross-drilled & tapped for four 3mm grubscrews to tightly
> grip the square. That should go into a collet nicely. You could
> perhaps slit longitudinally for that application, but a good tap fit
> should make that unnecessary. Concentricity will be better if the
> outside is turned, remedying both stock out-of-roundness and chuck
> eccentricity, I figure.
>
> As I used them manually, I had a drilled hole in the back, to slip
> over the drill bit still in the mill/drill chuck, for plumbing during
> hand tapping of the hole just drilled. A slice of 1" round, drilled to
> fit over the 1/2", and slotted externally to take the screws of a 1"
> dieholder slipped over, was added for manual tapping. (I've yet to
> find an adequate tap holder, and the die holder doesn't get in the way
> of the plumbing hole in the top.)
>
> The DIY path ensures you don't clutter the place with too many of 'em.
> I've only made three so far. (Made mine in brass, as it's delightful
> to machine.)
>
> Erik

And the grub screws stayed tight? The die holder I'd have to make as all 
mine are handled for 2 handed use.. Ignore that grinding noise, its just 
me thinking. Send me a PM with a couple pix if you can.

Thanks Erik.

-- 
Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page 

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Re: [Emc-users] Where are you getting R8 square collets for driving taps?

[Gene Heskett]

On Wednesday 07 March 2018 00:00:13 jeremy youngs wrote:

> Snip
> You might try an er 20 all I have ever used to rigid tap. They were
> also in cat 40 and 50 taper holders , tightened with wrench on bench
> so that maybe a thing. I have tapped up to 1/1/2 inch with er 20 sets.

I think that calls for a pix Jeremy.

Another thought comes to mind, the shars SK version collet which has a 
much longer rear taper, which should get a better grip. I'll check their 
catalog. Nope, no R8 to SK collets in it.

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-- 
Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page 

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Re: [Emc-users] Where are you getting R8 square collets for driving taps?

[Gene Heskett]

On Tuesday 06 March 2018 23:31:20 Jon Elson wrote:

> On 03/06/2018 10:05 PM, Gene Heskett wrote:
> > Greetings all;
> >
> > It appears that its well nigh impossible to get a firm enough grip
> > on a tap shank, and on the smooth, unkeyed TTS ER-32 holder, to
> > reliably lock a tap for rigid tapping.  I've considered buying
> > ER-32's with square sockets, but for >8mm taps, the TTS
> > adapter/holder will spin in the R8.
>
> There are tap chucks that have a round shank, and will fit
> in collets or end mill holders.
> You can also take the handle out and use a standard tap
> handle in a collet or big Jacobs chuck, although come of
> them are not centered well.

I've tried that several times Jon, and the resultant eccentricity pretty 
much makes a 9-32 hole using an 8-32 tap. That crap is stamped out of 
wheel weights I think. Perhaps I could braze on an expansion sleeve, 
then turn it true, bringing it up to 3/4 in diameter for better traction 
in the R8. But whats needed as a universal fix, is an R8 to tap thats 
keyed. I'm thinking of, when I can locate the square socket R8's, boring 
it round for 1/2" or so, and only 5 thou bigger than the opposing corner 
to opposing corner of the tap. That should hold the tap fairly true.
>
> I do rigid tapping with small taps, but have gone up to
> 10-32 without slipping.

A 10-32 in alu is usually ok, but an 8mm in steel is not a working setup 
here, and this is with 15 to 17 inch long wrenches tightening the ER-32 
nut. The limit there is the drawbar's teeny little square butt. I could 
put an 8 point socket on it, but by the time its truly locked, I can 
feel the threads on the bolt, or in the collet, giving way.  And gaining 
access to replace the drawbolt in a G0704 is, because my spindle encoder 
is in the way, not a very quickly done job.
>
> Jon
>
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-- 
Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page 

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Re: [Emc-users] Where are you getting R8 square collets for driving taps?

[Erik Christiansen]

On 06.03.18 23:05, Gene Heskett wrote:
> It appears that its well nigh impossible to get a firm enough grip on a 
> tap shank, and on the smooth, unkeyed TTS ER-32 holder, to reliably lock 
> a tap for rigid tapping.  I've considered buying ER-32's with square 
> sockets, but for >8mm taps, the TTS adapter/holder will spin in the R8.

The only thing I could suggest is the guts of some "tap-hats" I made -
that's just a length of 1/2" round drilled/bored to take the tap shank,
and cross-drilled & tapped for four 3mm grubscrews to tightly grip the
square. That should go into a collet nicely. You could perhaps slit
longitudinally for that application, but a good tap fit should make that
unnecessary. Concentricity will be better if the outside is turned,
remedying both stock out-of-roundness and chuck eccentricity, I figure.

As I used them manually, I had a drilled hole in the back, to slip over
the drill bit still in the mill/drill chuck, for plumbing during hand
tapping of the hole just drilled. A slice of 1" round, drilled to fit
over the 1/2", and slotted externally to take the screws of a 1"
dieholder slipped over, was added for manual tapping. (I've yet to find
an adequate tap holder, and the die holder doesn't get in the way of the
plumbing hole in the top.)

The DIY path ensures you don't clutter the place with too many of 'em.
I've only made three so far. (Made mine in brass, as it's delightful to
machine.)

Erik

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Re: [Emc-users] Where are you getting R8 square collets for driving taps?

[jeremy youngs]

Snip
You might try an er 20 all I have ever used to rigid tap. They were also in
cat 40 and 50 taper holders , tightened with wrench on bench so that maybe
a thing. I have tapped up to 1/1/2 inch with er 20 sets.
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Re: [Emc-users] Where are you getting R8 square collets for driving taps?

[Jon Elson]

On 03/06/2018 10:05 PM, Gene Heskett wrote:

Greetings all;

It appears that its well nigh impossible to get a firm enough grip on a
tap shank, and on the smooth, unkeyed TTS ER-32 holder, to reliably lock
a tap for rigid tapping.  I've considered buying ER-32's with square
sockets, but for >8mm taps, the TTS adapter/holder will spin in the R8.


There are tap chucks that have a round shank, and will fit 
in collets or end mill holders.
You can also take the handle out and use a standard tap 
handle in a collet or big Jacobs chuck, although come of 
them are not centered well.


I do rigid tapping with small taps, but have gone up to 
10-32 without slipping.


Jon

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[Emc-users] Where are you getting R8 square collets for driving taps?

[Gene Heskett]

Greetings all;

It appears that its well nigh impossible to get a firm enough grip on a 
tap shank, and on the smooth, unkeyed TTS ER-32 holder, to reliably lock 
a tap for rigid tapping.  I've considered buying ER-32's with square 
sockets, but for >8mm taps, the TTS adapter/holder will spin in the R8.

So the only way is to buy R8's with square bores, which, given the length 
of the square on the end of the tap, seems to be a better way, for some 
definition of "better".

In my search for such beasts, I find several Chinese makers, 
unfortunately with minimum orders of 10 each usually attached. There are 
none to be found on ebay, and apparently the only US seller must be gold 
plating them as they're running from $15 each on up.

If I was to buy 10 of each metric size, 3mm to 14mm and some come in .5mm 
sizes, I'd have several thou $ tied up. Making boxes to hold one of each 
size could be done, making a kit of around 20 pieces. At say $175 a kit, 
how many could I resell to those of you in the US in an effort to at 
least break even & leave me with a kit?

For those of you lucky enough to have some of these, are they truly an 
answer for this problem?, or something that works only if your chew of 
Kentucky Twist is just so. I am not personally impressed with something 
that grips only the square of a taps butt end, but it would for me, be 
better than at present.

Thanks.

-- 
Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page 

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