Milling chuck - Is that normal?

[Robert1998]

Hi everyone.

I have bought this milling collect chuck (ER25) and the "lid" has a non concentric ring. I think that ring is the part that pushes in the collect. The green hole is right, but the red one is non concentric



Here is the picture without colors.



Is that normal?

Thank you

Best regards

 

[Fastdruid]

Yes.

 

[Fastdruid]

The collets "clip" in to the nut and that holds them in place as you then tighten it up. The important bit to be concentric is the (presumably precision) ground tapered section at the front (or bottom in your pictures).

 

[skotl]

As above, yes: I got caught out with this with my first collet chuck too

 

[Kram]

The eccentric ring is the bit that allows collets to be loosened and pulled out after use. They could get very stuck in the taper if it wasnt there!

 

[Fastdruid]

On a related note you can't fit something in to the collet and *then* fit the nut (which you may want to do if it's half a smidge oversize). You need to fit the collet into the nut and *then* insert the shaft (and then fit to the holder).

 

[Misterg]

Good description on Arc Eurotrade’s site

 

[Robert1998]

I love this forum!

Thank for all your answers!

 

[Stupoty]

Don’t try to fit the cutter to the collet before fitting the collet to the holder! Many have tried and failed.. If they ‘manage’ it the run-out will be horrible, along with the proper clamping required.

Unless the nut is a bearing type, it likely needs towards a hundred Newton-metres torque. Do not tighten too loosely and risk the cutter slipping, or the collets will be toast for proper precision.

I have two ER32 collet things , a milling chuck and a lathe chuck, the lathe chuck nut doesn't let you insert it with something in the collet but the milling chuck is fine with it.

I only found out about the insert part/tool after collet after getting the lath chuck one.

Stu

 

[Stupoty]

It’s not the chuck - it is the nut which should be a tighter fit, although the collet fitted with minimum-sized cutter might go in, I suppose. Do bear in mind that the collets are only as per spec for the nominal largest size of cutter shank. Swap the nuts over and it will be the other way round.

I have two chucks but about five nuts for my ER32 size. Only two nuts for my ER16. They help to speed up cutter changes at times.

Yeah sorry I should have said that , the nut that wont let you have a tool in the collet is a much "stiffer" fit in general , the other one has a slightly looser tolerance feel but both seem to snug up to a similar run out level.

I had never come across this and thought my second one was faulty (turned out to be user error ha ha)

Stu

 

[slim_boy_fat]

I usually put the collet into the nut with a slight 'twisting' action, same on removal.

 

[Bki26]

Hi everyone.

I have bought this milling collect chuck (ER25) and the "lid" has a non concentric ring. I think that ring is the part that pushes in the collect. The green hole is right, but the red one is non concentric



Here is the picture without colors.



Is that normal?

Thank you

Best regards

I didn't realise this and thought it was just a ****ty manufacturing error with the clarke Cmd10 mill I got so removed it on the lathe before realising