Where to buy 6.5mm ER40 collet?

[Hollowpoint]

On Hollowpoint Said:

I did consider clocking it in a 4 jaw.. ..

Was going to say soft-jaws or ‘bored in situ’ split bush also accurate and cheap option..

I see I was beaten to it..

[Clive Brown 1Participant @clivebrown1]

I’d 2nd. using your Griptru 3-jaw and save your money. Once you understand the procedure it’s fairly quick and should be to 0.01mm or even better. A point to remember is that these chucks are really only repeatably accurate on the diameter that they’re set to, and then only if the same pinion is used. I always use the one adjacent to the PB logo. They’re very useful once youve got the hang of them.

[Martin KyteParticipant @martinkyte99762]

You really do need to find a way of doing it without needing an er collet. People have been solving problems like this long before collets were in wide use. It would help if you described the part. Maybe it is possible to do your machining and then turn the outside to 6.5mm all at the same setting. We need a drawing really.

[HollowpointParticipant @hollowpoint]

So the imperial collet I ordered (17/64) arrived today. Eager to get on with the job I put it in the chuck to test, 0.03mm! 😔 Even for a cheap one that’s pretty poor.

Sensing something must be amiss, I gave everything a good clean and retested the new collet and the original 7mm rego collet.

Imperial collet @ 6.5mm = 0.015

Rego collet @ 6.5mm = 0.008

Rego collet @ 7mm = 0.004

I can only assume that there must have been some debris in there or something. 🤷🏼‍♂️

[Clive Brown 1Participant @clivebrown1]

So does the original Rego collet at 6.5mm now meet your requirement; ie <0.01mm?

[Neil WyattModerator @neilwyatt]

I think it was Richard Gordon who found that by using a dial indicator and tapping the work gently as you tighten in stages you can minimise runout to tiny levels.

Of course that’s runout where the indicator is, so the work may not be perfectly axial…

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