Thought that there may be some interest in this, designed and 3d Printed an ER11 collet nut to fit my cheapo 850w router. Have run it through its paces and all is holding up well! Try at your own risk but would be interested to hear if anyone else has success with it. The ER11 opens up a lot more options for me with the HP behind the 240v router too!
Hmmm. I could imagine it working fine in nominal conditions, but if you had something wrong and the bit got hot, it will deform first (which might save you) and then catch fire. The only smoke I’ve had was when I drove the bit so far in the collet was hitting the work (we call it “Barrying the collet” because Barry did it first).
I like 3D printing parts for my CNC, but I wouldn’t want the bit to fly at me. Keep a fire extignuisher handy. The collet is a very important part of the whole thing.
It’s like a fuse–the bit gets hot which then transfers the heat to the collet, then to the collet nut, which melts, releasing pressure off the collet, so the endmill can free-spin, preventing it from catching the work on fire.
Good news is it should release the bit if you get excessive heat. Bad news is it might not release the bit in a graceful manner. It could get cocked to the side and snap and fly at you. But anyway a bit can already snap and fly at you, so I suppose it’s not any worse.
And seems to me the self-releasing collet should reduce chance of fire.