Could you clarify my suspicions. My spindle (HY HUANYANG, model: GDZ-80-2.2A) has come with a collet nut which has bizarre asymmetrical form of a supporting ring inside it (the ring for collet groove). Since I have obscure issue why all my end mills break with my CNC whereas they cut successfully with the same milling parameters on another CNC, I suspect the problem could lie here. Please take a look at the attached images I have taken for you and guide me please do I have to replace my collet nut or it's totally normal the ring asymmetry?
that off center ring is normal for an ER collet nut. when you put the collet into the nut it will center itself. (you must put the collet into the nut first, before screwing onto the spindle) then you put the nut+collet onto the spindle it will center even better.
When David said ... Just for clarity (I know that David knows this!) you must also clip the collet into the nut (simply putting it inside the nut isn't sufficient) - the collet needs to be tilted to one side so that it snaps past that eccentric retaining lip (which is perfectly normal). Your last picture looks as if you might not have done this (the face of the collet *usually* ends up flush with the nut). (Image from Arc Eurotrade: ER20 Collets - Arc Euro Trade ) If fitted correctly, the collet won't come out of the nut without springing it sideways again and pushing it out.
Also.. the ER nuts are cheap and you should buy enough to live with your most used collet sizes. saves time Cheers Gary
Yep, that's what I did too. I bought enough nuts for all my most used collets. I think they were like $2 a piece, or so.
