ER Collet

[Neil WyattModerator @neilwyatt]

Posted by Howard Lewis on 20/03/2016 17:00:58:

I don't bother with making the Closing Nut, too complcated, so just buy from Arc EuroTrade.

Don't blame you. My first time I made a closing nut and it took four specially ground toolbits from 1/8" HSS!

 

Next two closing nuts both ball bearing ones – one from Gloucester one from Arc

Also made an 8/82 degree square especially for setting myu top slide to the taper for both ER sockets and making my own 'emergency' collets.

Neil

Edited By Neil Wyatt on 20/03/2016 21:18:49

[Roy MParticipant @roym]

I have successfully converted an old BT40 ER32 holder for use on a lathe, simply by turning the taper into a shaft. I say 'simply', but although technically unchallenging, the metal removal was a bit of a struggle as the one I converted was a bit 'ard. It runs very true, and runout can be zero if held in a 4 jaw chuck. Roy M.

[Enough!Participant @enough]

Posted by Howard Lewis on 20/03/2016 17:00:58:

An ER collet Chuck for a lathe will be backplate mounted, and so allow material to pass through into the Headstock. As Roderick says, 15mm for Series 7 Myfords, so ER25, (unless you have one of the later 4MT Super Sigmas in which case ER32, possibly ER40)

FWIW the ER chucks for my ML7 mount directly to the Myford nose. They do allow material to pass through as you say but the bore diameter only makes a difference, of course, if and when you actually want to pass material through. In my case, much of the time I don't.

I have both ER25 and ER32 chucks for the lathe and use them both about equally. If I had to choose one over the other it would be ER32, no contest, since I use the larger sizes that ER32 only covers very much more frequently than the small sizes that ER25 only covers. Other peoples' mileage may vary of course.

I also incidentally (and accidentally) have an ER25 chuck on MT2 that I use in the tailstock sometimes.

On the mill (WM-16/18 equiv) I use ER32 exclusively since I often use 3/4" or 20 mm cutters and any smaller cutters (even quite tiny ones0 have shanks that will fit in the ER32 range. I also have a sprung-ball type of electronic edge finder which I use a lot and its body dia is 20mm.

[ZebethyalParticipant @zebethyal]

If you want a cheap, short, spindle mounted ER32 collet chuck that permits stock to pass through the spindle, how does £19.00 sound?

Buy yourself Stevenson hexagonal ER32 collet block from Arc (£19.00 or £17.75 if bought with the square collet block at £35.50 for the pair), then machine the required nose thread in the rear of the fixture.

There should be enough length of unused stock beyond the end of the ER32 taper to clear the spindle nose threads.

You can then either use a large spanner to remove it, or add some holes for a tommy bar.

Doubles up as a six sided fixture )

Having a Mellor lathe with 1 1/4 x 9TPI spindle thread means that I need to be creative with regards new chuck options, since actual Mellor threaded chucks seem to be rarer than rocking horse poop. My other option of course is to machine my own backplates.

[Piero FranchiParticipant @pierofranchi37209]

what a simple grate idea Timothy

top marks

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Timothy Moores on 21/03/2016 08:06:18:

If you want a cheap, short, spindle mounted ER32 collet chuck that permits stock to pass through the spindle, how does £19.00 sound? … < etc. >

.

The Man's a genius

MichaelG.

[AjohnwParticipant @ajohnw51620]

Posted by Michael Gilligan on 21/03/2016 18:08:39:

Posted by Timothy Moores on 21/03/2016 08:06:18:

If you want a cheap, short, spindle mounted ER32 collet chuck that permits stock to pass through the spindle, how does £19.00 sound? … < etc. >

.

The Man's a genius

MichaelG.

 

I had been thinking about that since seeing them but wondered how hard the material was so might give it a go now. Also other options by mounting it on a piece of turned bar with a collet in it and machining as needed.

In terms of making an entire holder I feel it really is best to buy the nut.

John

–

Edited By Ajohnw on 21/03/2016 19:26:33

Edited By Ajohnw on 21/03/2016 19:27:42

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Ajohnw on 21/03/2016 19:26:01:

I had been thinking about that since seeing them …

.

O.K. … You're a genius too, John

[Piero FranchiParticipant @pierofranchi37209]

I have decided to go with ER 40 collets.
Will just suit my needs better.
Am loving the collet block idea.

As to the ER 40 collet.
How does ?90 for a set of 23 sound.

It’s from a UK London based flea bay seller

[Piero FranchiParticipant @pierofranchi37209]

Hope this is ok, but here is the flea bay link to the set,

one thing I did note, it does not specify a tollerance

http://www.ebay.co.uk/itm/361358171050?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

[Jon GibbsParticipant @jongibbs59756]

Posted by Ajohnw on 21/03/2016 19:26:01:

Posted by Michael Gilligan on 21/03/2016 18:08:39:

Posted by Timothy Moores on 21/03/2016 08:06:18:

If you want a cheap, short, spindle mounted ER32 collet chuck that permits stock to pass through the spindle, how does £19.00 sound? … < etc. >

.

The Man's a genius

MichaelG.

 

I had been thinking about that since seeing them but wondered how hard the material was so might give it a go now. Also other options by mounting it on a piece of turned bar with a collet in it and machining as needed.

In terms of making an entire holder I feel it really is best to buy the nut.

I hate to pour cold water on this idea but, having made a few ER collet chucks for my lathes, the hardest part by far is getting the internal thread to fit the lathe nose with sufficient precision. The internal taper and the external thread with the embryo chuck screwed onto the nose thread are then a doddle by comparison and pretty much guaranteed to be concentric – especially if you follow HH's instructions.

+1 for buying your nuts though

Jon

Edited By Jon Gibbs on 22/03/2016 09:01:49

[HollowpointParticipant @hollowpoint]

Posted by Piero Franchi on 22/03/2016 07:45:15:

Hope this is ok, but here is the flea bay link to the set,

one thing I did note, it does not specify a tollerance

http://www.ebay.co.uk/itm/361358171050?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Makes them just under £4 each. You won't get them any cheaper than that but as you say no mention of run-out. Arc euro do them at £5 each and they seem decent. I'll message you the link to the Swiss made ones I bought.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Jon Gibbs on 22/03/2016 08:53:21:

I hate to pour cold water on this idea but, having made a few ER collet chucks for my lathes, the hardest part by far is getting the internal thread to fit the lathe nose with sufficient precision.

.

If that nice Mr Stevenson would make them ready-threaded for the Myford spindle nose [leaving the register a few thou undersize, for final finishing] … the job would be a doddle.

MichaelG.

[john fletcher 1Participant @johnfletcher1]

John Gibbs mentioned HH's instructions, where might I find then. Also I like Michael idea, that if John can be persuaded to make his blocks with the thread already there that would be even better and possible improve his sale .John

[Jon GibbsParticipant @jongibbs59756]

Posted by john fletcher 1 on 22/03/2016 11:04:13:

John Gibbs mentioned HH's instructions, where might I find then. Also I like Michael idea, that if John can be persuaded to make his blocks with the thread already there that would be even better and possible improve his sale .John

Here they are… **LINK**

Jon

[AjohnwParticipant @ajohnw51620]

Posted by Jon Gibbs on 22/03/2016 08:53:21:

Posted by Ajohnw on 21/03/2016 19:26:01:

Posted by Michael Gilligan on 21/03/2016 18:08:39:

Posted by Timothy Moores on 21/03/2016 08:06:18:

If you want a cheap, short, spindle mounted ER32 collet chuck that permits stock to pass through the spindle, how does £19.00 sound? … < etc. >

.

The Man's a genius

MichaelG.

I had been thinking about that since seeing them but wondered how hard the material was so might give it a go now. Also other options by mounting it on a piece of turned bar with a collet in it and machining as needed.

In terms of making an entire holder I feel it really is best to buy the nut.

I hate to pour cold water on this idea but, having made a few ER collet chucks for my lathes, the hardest part by far is getting the internal thread to fit the lathe nose with sufficient precision. The internal taper and the external thread with the embryo chuck screwed onto the nose thread are then a doddle by comparison and pretty much guaranteed to be concentric – especially if you follow HH's instructions.

+1 for buying your nuts though

Jon

Edited By Jon Gibbs on 22/03/2016 09:01:49

When making back plates etc it really is best to have a very accurate dummy spindle nose available but Jon does have a point. The thread flanks have to be correct on the dummy nose as well. The one that came with my boxford is nvg in that respect so another job to do when needed.

The nut is interesting. I was talking to one of the retailers and they were having problems with the screw on er chucks and I pointed out that they would be best made on the lathe really and what people have been known to get up to machining spindle noses etc. It needs a light force fit really. Hard to achieve and the thread needs to be rather true too. I told him that I wouldn't make a nut – to hard in several respects which surprised him as he knew where I was trained.

I bought one of the screw on ones and sent it back. The problem was a mix of front to back alignment including the thread being out more and the fit.

John

–

[Piero FranchiParticipant @pierofranchi37209]

how would clamping the hex collet block in a 3 jaw chuck work???

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Piero Franchi on 22/03/2016 16:43:45:

how would clamping the hex collet block in a 3 jaw chuck work???

.

Very badly [if the 3-jaw is typical]; eccentricity is likely to be at least 10x what you might reasonably expect from a collet.

… On the other hand; your 3-jaw might be very very good.

MichaelG.

Edited By Michael Gilligan on 22/03/2016 16:58:42

[Jon GibbsParticipant @jongibbs59756]

+1 for Michael's comments. If you have a 4-jaw chuck you'd be much better off with a 4-sided block held in that. Your accuracy would then only be limited by your indicator precision and your patience.

Jon

[AjohnwParticipant @ajohnw51620]

If some one want highs accuracy on something with significant length the best answer is to make a cup chuck with 2 rows of 4 holes.

Even more interesting to set up and seldom seen these days for some reason.

I would be careful about accuracy claims on ER collets, Some are just the run out of the front of the bore. I am not even sure that when the din spec number and a tolerance is quoted if it is as it should be – run out some distance from the nose of the collet which I think gets longer as the diameter goes up.

John

–

[Michael GilliganParticipant @michaelgilligan61133]

John,

Regarding the DIN spec … the "some distance" is given in the brochure that I referenced last time we discussed DIN 6343

MichaelG.

Edited By Michael Gilligan on 22/03/2016 22:58:24

[AjohnwParticipant @ajohnw51620]

Posted by Michael Gilligan on 22/03/2016 22:53:38:

John,

Regarding the DIN spec … the "some distance" is given in the brochure that I referenced last time we discussed DIN 6343

MichaelG.

Edited By Michael Gilligan on 22/03/2016 22:58:24

Sorry Michael I should have remembered that but it's good to have a link to that here as well. The ebay limits do often just give one figure though neglecting size. I have seen one listing somewhere that points out that their better standard can not be supplied below a certain size.

John

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[Russell EberhardtParticipant @russelleberhardt48058]

I see little point in converting a collet block to screw onto the spindle nose. It wil take a good deal of skill to ensure that the register lines up accurately with the existing taper socket. The idea of machining the register and spindle nose thread first is to ensure that the taper is lined up with the register. As long as the register is accurately dimensioned and the thread is not too tight the collet chuck will seat well. If the taper is then machined it cannot be other than truly aligned with the spindle axis.

Russell.

[Michael GilliganParticipant @michaelgilligan61133]

Russell,

Perhaps I missing some important point, but: Would 'jigging' it not be a simple matter of turning a suitable 'stub mandrel' and clamping the collet onto that ?

MichaelG.

[Martin KyteParticipant @martinkyte99762]

However . . . There is nothing to stop you mounting your collet block in a 4 Jaw and clocking true. You then have a system in which you can remove and replace items at will. Without re-clocking. It's certainly been done with a small 3 Jaw in a Bigger 4 Jaw. You can also do repeatable excentric turning this way.

[Author]

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