ER40 square collets

Does anyone know if there is a supplier for ER40 collets to take square material please?

I've never seen square ER collets but this might help - although admittedly it requires a lot more work... **LINK**

HTH

Jon

If you are lucky square stock can be held in a standard ER collet, I have done it a few times with no provlem, just holds the work by the corners so no heavy cuts.

What shank is your ER40 collet holder?

Jason, thanks for that! Wanted to face off and drill the end of some 16mm brass square, corners fitted nicely into the slots of a 22mm collet, job done!

David, not sure why it's interesting, but it isn't a shank it just fits on the Super 7 spindle nose.

Interesting point. I've used square stock in my ER32 chuck but which is best, locate the corners of the stock in the slots of the collet or between the slots?

Edited By Vic on 13/04/2017 17:54:47

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Given that ER collets are slotted 'out of phase' at each end ... I suspect that whichever way you try to do it, it will end up 'half & half' [so the choice is really whether the front or back end is better in the slots].

MichaelG.

Also depends on how many slots the collet has, some have 6 each end, some have 8 each end./

If you set the corners about 1/4 of the space from the front slots they won't touch the back slots either on an 8 slotter, easier to do on larger sizes than small.

Whatever, it worked very well.

I would've thought that with the square collets you aren't able to use or assume that you'll get the same big size range as an ER40 collet would give you with round stock.

Same with all collets such as 5C square ones you will always be limited to the across corners dimension so ER40 would only go upto about 18mm square which is 26mm across corners

ER collets also work very nicely on shallow angle tapers :D

Not sure if they were made by some one or a purchased item, but we used to have a segmented piece held by 2 wire clips. The segments allowed you to hold a square bar in a collet and went up to 3/4" square. The smallest was like 3/16 or so. They were all imperial. it was just 4 cord segments retained with a wire clip at each end and used in the collet chuck.

Neil

I asked because you can get a square section holding 5c collet plus a cnc collet holding bushing with a parallel shank, but unfortunately the bushing is too big to go in an ER32 collet.

I have just used my ER25 collet set to hold a piece of 1/4" square brass to machine the fork end for the eccentric rod fitting for my S50 yesterday, it held it in the slots quite securely & didn't need any centering, the 7BA tapping hole was bang on centre, so I would have any hesitation in using this method again ( Have used the 16 mm collet in the same manner for a large 5/8 " hexagonal bar ).

One thing to be aware of; some collets have the diameter size that only goes 1/2 way along the inside of the collet then opens out to a larger dia. ( clearance ) so if you need to machine a tiny piece then you need to put a same diameter offcut in the back of the collet to even out the clamping forces, or may be a larger dia. to fill the back of the collet otherwise you will clamp unevenly & possibly have the small piece come flying out of the collet or even damaging the collet, worth bearing in mind.

George.

A self centring four jaw would be a better option, there are some decent and inexpensive ones out there, mines a Tos which I've had for about six years and use all the time, in fact the only time I use a three jaw these days is to hold hexagonal stock.

AS far as I know, ER collets are only produced to hold round workpieces.

Unless I am mistaken, was'n there an article some time ago on making a set of parts to hold square material in a round ER collet?

ER40 should be large enough to accomodate "adaptors" of various sizes.

Howard

Howard,

You are correct, there was an article in MEW a few yearsago. I made 4 sets to suit differing sizes of square bar and found them very handy on numerous occassions. I`ll see if I can find the source reference as I should have it somewhere.

Alan

See the link in the second post, most likely the article was by Harold.