COLLET CHUCKS

This topic has 12 replies, 9 voices, and was last updated 12 February 2013 at 13:03 by _Paul_.

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9 February 2013 at 09:56 #111434
RICHARD GREEN 2
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@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.
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9 February 2013 at 09:56 #12081
RICHARD GREEN 2
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@richardgreen2
9 February 2013 at 10:12 #111436
David Clark 13
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@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
9 February 2013 at 10:33 #111442
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
9 February 2013 at 10:49 #111444
Michael Gilligan
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@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.
9 February 2013 at 11:28 #111451
Frank.N Storm
Participant
@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
9 February 2013 at 12:55 #111454
David Littlewood
Participant
@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
9 February 2013 at 13:15 #111457
Michael Gilligan
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@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.
9 February 2013 at 13:49 #111462
Sub Mandrel
Participant
@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
11 February 2013 at 22:18 #111794
David Littlewood
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@davidlittlewood51847
Thanks Michael and Neil.

David
12 February 2013 at 12:24 #111853
colin hawes
Participant
@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
12 February 2013 at 12:57 #111858
Michael Gilligan
Participant
@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.
12 February 2013 at 13:03 #111859
_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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