Some advice on ER collets

[grim_d]

My CNC router uses ER20 on the spindle and I've noticed yesterday that the taper in the nut appears to be chewing up the nose of the collets.

I'd like to know if this is at all normal (can't imagine so) for ER collets used with a plain collet but? My bigger collets I exclusively use ball bearing nuts so the nut does not rub on the collet and as such I've never experienced this.

The nut has matching marks, like the collet has picked up a bit of the nut at some point, the nut is the one that came with the machine but the collets are decent. I think I'll pick up a couple bearing nuts, just don't know how long they will last with the wood dust.

 

[Munkul]

Both collet and nut are probably softer than ideal. Can you convert it to a ball bearing nut?

 

[Kram]

Nothing like that on any of mine with normal nuts and I wouldnt expect wood dust to do that.

 

[grim_d]

Both collet and nut are probably softer than ideal. Can you convert it to a ball bearing nut?

Yes I'm going to give them a try, see how long they last as it's a very hostile environment for a bearing.

The collets were good quality items too

Nothing like that on any of mine with normal nuts and I wouldnt expect wood dust to do that.

Thanks, I dont think it's the dust or debris as I clean between changes, I think it's picked up some material from the softer nut.

 

[Hopefuldave]

I'm going to ask a seemingly insulting question....

You are clicking the collet into the nut first, then both together into the chuck? ER collets have the groove for the *extractor ring* in the nut, you have to engage them (tilt the collet so the groove fits over the ring, then straighten - the front of the collet should be flush with the front of the ring).

The damage in those collets matches where the ring would hit if they're not assembled right...

Dave H. (the other one)

 

[MattF]

Possibly nut not tightened fully, and the collet's spinning?

 

[grim_d]

I'm going to ask a seemingly insulting question....

You are clicking the collet into the nut first, then both together into the chuck? ER collets have the groove for the *extractor ring* in the nut, you have to engage them (tilt the collet so the groove fits over the ring, then straighten - the front of the collet should be flush with the front of the ring).

The damage in those collets matches where the ring would hit if they're not assembled right...

Dave H. (the other one)

How dare you.

Worry not, I'm using them correctly, all my other ER collets are fine.

Reminds me of an AvE video where he thought the nut was faulty and machined the groove away.

Possibly nut not tightened fully, and the collet's spinning?

Nah, I noticed it after it started "squeaking" when I was tightening it.

I think I'm just going to put it down to the cheap Chinese nut that came with the cheap Chinese spindle attached to the expensive Chinese machine.