COLLET CHUCKS

[RICHARD GREEN 2Participant @richardgreen2]

I've always used Clarkson type collet chucks for holding milling cutters with 1" or larger shanks,

I recently bought a very nice Vertex ER40 collet chuck with a 40 INT taper,

My question is this,….. The Clarkson collet is threaded onto the shank of the cutter, and the collet is held firmly into the body of the chuck, when tightened the cutter cannot move up or down at all during heavy cuts,

However, the Vertex collet only grips the cutter on the plain part of it's diameter, and is not threaded onto the cutter at all, and I'm concerned that under load and taking heavy cuts the cutter would be able to move in the collet,

What do you think ?

Richard.

[RICHARD GREEN 2Participant @richardgreen2]

[David Clark 13Participant @davidclark13]

As long as you tighten it right up it should be fine.

I never had a problem with ER collets moving on CNC milling machines even when taking very large cuts, far larger than you could take on a home mill.

regards david

[Anonymous]

I've never had a problem with cutters slipping in ER collets, albeit on a smaller scale (ER20). The torques recommended for ER collets are quite high, see here:

**LINK**

Regards,

Andrew

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Andrew Johnston on 09/02/2013 10:33:26:

**LINK**

.

That's a very useful link; thanks Andrew

The "tightening fixture" also looks like it would make a useful work-holder

MichaelG.

[Frank.N StormParticipant @frank-nstorm18349]

Very good in principle – but what to think about a company called "techniksusa" constantly referencing torque units as ft/lbs ? Doubling the lbs gives half the torque, strange isn't it?

Sincerely, Frank

[David LittlewoodParticipant @davidlittlewood51847]

Yes, thanks Andrew. Do you have any idea where you could get – or how you would make – a torque wrench with an ER nut fitting at the business end?

David

[Michael GilliganParticipant @michaelgilligan61133]

Posted by David Littlewood on 09/02/2013 12:55:41:

Yes, thanks Andrew. Do you have any idea where you could get – or how you would make – a torque wrench with an ER nut fitting at the business end?

David

.

David,

This looks like a good place to start

MichaelG.

[Sub MandrelParticipant @submandrel]

Hi David,

The wrench supplied with teh chuck should be of a length such that a typical user will be able to fully tighten it without excessive effort and won't be able to damage it by over-tightening. The transition between sqeezing up the collet (which can be done with the hand only at ER25) and locking it should be obvious.

My home made ER25 chuck goes 'solid' very quickly as it grips the tool, and at this point I just give it what my Dad calls a 'nip'.

Neil

[David LittlewoodParticipant @davidlittlewood51847]

Thanks Michael and Neil.

David

[colin hawesParticipant @colinhawes85982]

I have used powerful CNC machines where the Clarkson chuck is not used as it was desirable to set the tool height initially by measuring it's projection from it's collet. These collets ,to my knowledge,never let a tool slip and they only gripped the plain part of an endmill. Colin

[Michael GilliganParticipant @michaelgilligan61133]

Just think how much money would have been saved, over the years, if the cutter manufacturers hadn't ground threads on all those cutter shanks !!

Apparently; all it needed was clever collets, slit both ends.

… There's a lesson to be learned.

MichaelG.

[_Paul_Participant @_paul_]

I use ER32 on just about everything, I have noticed a marked performance difference in the type of ER closing nuts, from experience the ones with an integral bearing take "less force" to grip than their plain counterparts and are less prone to slip.

If I do have an ER collet slip it's normally down to me not tightening it enough.

Like everything else though it comes with a price, on average the bearing type are 3 times more than the others.

Regards

Paul

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