Unknown spring collets

I have acquired 7 collets with metric bores but im unsure what they are for. Their length is 45mm +/- 0.5mm. The main taper is 10° included and a nose taper of 60° included. There is a parallel section between both tapers of 10mm length, 24mm diameter. The slot is 3.9mm wide. There are no markings on them other than their bore diameter.

Does anybody have any ideas what these might be? If it's of any help they came with a quantity of what I believe to be Schaublin W20 collets.

Thanks, Craig

Edited By Craig Brown 2 on 08/10/2022 07:18:53

If I recall correctly, Craig … I think they are the original E collets, that came before ER

MichaelG.

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Edit: __ my recollection was not quite good enough 

Try EX .. as per the final post on this page:

https://www.model-engineer.co.uk/forums/postings.asp?th=46975&p=2

Edited By Michael Gilligan on 08/10/2022 07:43:48

To the best of my knowledge, the Schaublin collets of E, EX and ESX all had the same taper angle and, ignoring the groove, projected side view (proportions/silhouette) as the later ER collets. They only differed in the presence or absence of the groove that retained them in the nut.

Hence, the Schaublin connection might be no more than sharing a box. It might help to add a picture of the ones you believe to be W20 as if they are not so, it might open other lines of enquiry.

The 10 degree taper is different to ER series collets (8 degrees). The overall length of 45mm is closest to ER40, but the 24mm diameter is between ER20 and ER 25. No ER or close relation has a parallel shank behind the groove.

Hence, the proportions are all wrong for ER - ER collets as a concept are short and fat, your own are are long and slim.

They look like TG Collets

Nigel B.

..beat me to it..

I stand [quite happily] corrected

… it’s a good day, when you learn something new

MichaelG.

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Edit: __ Now, for all you collet experts … here’s one that’s really got me beaten so far

Anyone with the right vintage of Crawford catalogue could probably just find it listed

… but that’s not I

It’s 0.500” bore, and clearly marked AS4/A

Edited By Michael Gilligan on 08/10/2022 09:17:32

The dimensions in the link you post do not match the dimensions posted by the OP so you would need to expand on what you mean by 'look like'.

Forgot to mention … Here, if anyone needs it, is the Schaublin catalogue: **LINK**

http://www.schaublin.ch/app/webroot/pdf/cat/5.pdf

MichaelG.

Thanks for all the comments and suggestions so far. I did first think they might be an early version of an ER collet but, as mentioned above, they were the same as an ER collet in every way but just didn't have a slot. ER have an included angle of 16° whereas mine are 10°.

Again they look sort of similar to the TG collets but the dimentions don't tie up.

These are the Schaublin collets, I believe the marking to denote schaublin, they have a 20mm main body diameter and a bizarre specification of buttress thread. Thats why I think they are W20. I actually purchased them in the hope they were 3C so didn't do very well really.

Chinese ERalike collets possibly, quite a few of our suppliers sold them around 2005 to 2010 before ER became much more common, even ARC sold them and this is an image taken from their catalogue at the time. I have a full set of metric and imperial but seldom use them now

Edited By JasonB on 08/10/2022 13:22:43

I think you are correct. It is not too hard to make a holder for them. The difficult part is the buttress thread. rcm-machine sell a female W20 to female M12 adaptor which might help.

---

I wonder if the old Arc catalogues are going to become collector's items in the same way that Americans seek after McMaster ones.

Thanks, looking at that image I should say thats exactly what they are. Not much use without the collet holder. If anyone has any use of these then let me know.

Whilst we are on collets … This may be of interest to some:

DIN ISO 15488 [previously DIN 6499 according to this Supplier: https://www.fwt-gmbh.de/en/clamping-nut-for-collets-er ] makes a ‘use case’ distinction between 8° Collets of Form A and Form B

**LINK**

https://www.iso.org/standard/36756.html

[quote]

Form A applies to milling and any other application where a hard collet bore is required, provided that the clamping range of h10 be sufficient. Form B applies for general purposes where an extended clamping range is required.

[/quote]

So … the form that everyone likes, because of its extended range, is for ‘general purposes’ not for milling.

Feel free to discuss

MichaelG.

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P.S. __ I found this “preview” of the Standard : https://cdn.standards.iteh.ai/samples/36756/2c2f56ee87314089a6178dea802b3921/ISO-15488-2003.pdf

[ but the Moderators might decide to remove the link ]

Edited By Michael Gilligan on 09/10/2022 23:15:28

Edited By Michael Gilligan on 09/10/2022 23:20:14

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Just to satisfy my curiosity, Jason … may I ask for a photo of the holder for those collets ?

At first sight, the inclusion of that cylindrical section seems counter-intuitive.

MichaelG.

Idea was/is, to fit the collet into the screw cap, the bore of which allows the nose of the collet to be sprung into it and then fit this into the holder body. Rather than use a Birmingham screwdriver to extract the collet, the cap acts as a jacking screw. If the face of the cylindrical section wasn't there, it would be difficult clamping anything in the collet.

Regards Ian.

Edited By Circlip on 10/10/2022 08:41:12

There is an OZ collet and the taper is 1:10 or 5.71 degrees per side, or about 11.42 degrees included angle. They were quite popular with Hare and Forbes, and other spindle adapter types as well. The front is 30 deg taper per side like an ER collet but with less taper in the main part.

There are a lot of different collets around for sure, and trying to figure them all out is not an easy thing.

We have at work another odd ball collet with the main part only being 4 deg per side, or 8 deg included angle, but the top is flat .

Michael, they are very much like ER collets and snap into the nut in the same way with the eccentric lip in the nut. The long taper seats fully in the holder with the short straight section protruding. So it is really just the two tapers that do the business.

The cylindrical section probably makes manufacturing tolerances a little less demanding - that long thread(!) would allow a lot of variation in the taper position..

Neil

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Thanks, Jason

MichaelG.

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Ian,

Should I understand from your comment ^^^ that you believe the standard-length ER collet is not fit for purpose?

… or am I missing some subtlety in that assertion?

MichaelG.