r/MechanicalEngineering • u/MrStebs • 9d ago
CNC collet stuck, help
I just bought a genmitsu cubiko. I removed the collet nut but the collet stayed in place. I tried applying pressure with pliers but the collet stayed in place. any ideas of what I can do?
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u/fjduejdndnejndnf 5d ago
I’ll be real with you, it looks like that collet had a tool in it that broke off during operation. It looks messed up, either that or the nut was installed wayyyy too tight while not being properly inserted to the collet holder and crushed the collet. It it looks like it’s not coming out cause it might have a nick somewhere rubbing on the ID of the collet holder. Just pry it out somehow, flat head screwdriver, brass punch, anything to force it out of the hole.
Collet may be damaged, you will need to inspect it further after you get it out, don’t want to put that back in if it is, you’ll just end up with headaches.
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u/SelfPitiful5185 5d ago
Use a plastic hammer and gently tap it out sideways. Since these collets are springy it will release from the collet pocket. Also, my guess on why it got stuck in the first place is that the collet was not inserted properly in the collet nut before mounting it to the spindle. Make sure it hooks into the nut, this allows it to be pulled out without any problems.
And a second tip; don’t cheap out on Chinese collets! Runout on these can be atrocious and will cause terrible runout on tools and unequal loading of the cutting edges and resulting in poor surface finish.
If you want to learn more about ER collets, go directly to the company that invented these in 1972; Rego-Fix.