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Looking for collets from mystery collet holder

 

Good day,
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Would anyone have an idea about the collet system for the attached collets and collet holder? I got these in a lot of unassorted tools and had to produce a new back plate - which had been missing.
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Someone suggested to me today that the collets bear some resemblance to , but the collet angle and dimensions on mine are different. I will give these here:
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d = 16
L = 29,9
A = 16,4
D = 20,8
¦Á = probably 25o
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Bare colletholder.jpg
Bare colletholder viewed askance from above.jpg
Colletholder with collet, retaining cap removed.jpg
Colletholder with collet mounted.jpg
Collets runing from 2mm to 10mm.jpg

 

I have a box of collets like these, but bigger, probably as described on your linked page. I always assumed they were the sort of collets you would use in a machine having a bar feed through the headstock. They can be arranged to close from behind so they don't retract, so the bar doesn't move back when you tighten the collet. The set I have came with an old Myford, which had no holder or anything else which could be used with them. Thanks to your link I can at least identify them. I've seen lots of these around but never seen them used.
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Looking around I found this link which includes the title of the standard - Collets - dead length type. This suggests that My earlier thoughts are along the right lines. Looking further I find which shows them being used on bar feed machines, and just about shows how they operate.
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This leads me to think abut the collets or whatever that are used on NC lathes, where I've seen them feeding the bar through while turning it to size, so the bar moves past the toolbit, which stays still. So the collet has to relax enough to let the bar slide, but maintain drive and concentricity. Something clever going on.
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Anyway, the DIN 6343 seems to cover a limited range of sizes. Maybe another standard covers smaller ones, or someone decided to make some similar to the standard ones. Then again I suspect quite a range of these collets were made before the standard existed, and I bet each manufacturer made theirs a bit different to everyone else, so you couldn't easily switch to a different supplier
 

As always, many thanks for your exhaustive reply, Keith.
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Jan van der Laan, who is also on this forum, had suggested to me basically the same thing. According to him too, the collet system is a dead length type, for which he provided (in Dutch). Seeing that it was called there a QTH 161E, I searched for that term, which then led me to QTH for Traub lathes.
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I am glad that my set of collets is now a few steps closer to identfication. Not sure whether I will try to push stock through the collets, though. As it is, they are quite precise so for the time being I simply use them as "normal" collets. Just missing collets of size 1, 1 1/2, 7 and 9 mm but I am happy to have this set anyhow. One final consideration though - the set came in a sale which also contained the EMCO Unimat clockmaker's package, Could it be that horologists might have seen a use for these dead length/push type collets?
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Herman?

Op 03-12-2024 07:13 CET schreef Keith S. Angus via groups.io <keithsangus@...>:
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I have a box of collets like these, but bigger, probably as described on your linked page. I always assumed they were the sort of collets you would use in a machine having a bar feed through the headstock. They can be arranged to close from behind so they don't retract, so the bar doesn't move back when you tighten the collet. The set I have came with an old Myford, which had no holder or anything else which could be used with them. Thanks to your link I can at least identify them. I've seen lots of these around but never seen them used.
?
Looking around I found this link which includes the title of the standard - Collets - dead length type. This suggests that My earlier thoughts are along the right lines. Looking further I find which shows them being used on bar feed machines, and just about shows how they operate.
?
This leads me to think abut the collets or whatever that are used on NC lathes, where I've seen them feeding the bar through while turning it to size, so the bar moves past the toolbit, which stays still. So the collet has to relax enough to let the bar slide, but maintain drive and concentricity. Something clever going on.
?
Anyway, the DIN 6343 seems to cover a limited range of sizes. Maybe another standard covers smaller ones, or someone decided to make some similar to the standard ones. Then again I suspect quite a range of these collets were made before the standard existed, and I bet each manufacturer made theirs a bit different to everyone else, so you couldn't easily switch to a different supplier

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