Nearly lost a finger to a collet nut last Tuesday - be careful out there

I was changing tools on our Haas VF-2 at the shop in Cleveland around 4 PM and the collet nut wasn't fully seated. When I hit the spindle start it came loose and flew off, bounced off the enclosure door and nearly took my hand off. It hit the concrete floor so hard it left a dent and a chip in the nut. Has anyone else had a tool holder come loose like that or am I the only one who got lucky?

2 comments

2 Comments

diana_west271d ago

Ngl I read about a guy on Practical Machinist last year who had a CAT40 holder come loose on a Matsuura and it went through the side window of the enclosure like a bullet. He said the dent in the floor was almost an inch deep. Your story sounds pretty close to that honestly. That collet nut velocity is no joke when it lets go. Glad you didn't lose that finger man.

felix_black1d ago

It ties into something I've noticed with a lot of mechanical stuff in general. People think of tool holders as just a chunk of metal, but the energy stored in a spinning tool is wild. Like how a car's lug nut will snap off if you hit the curb wrong, or how a chainsaw chain can explode if it hits a rock. We just assume these things are solid until they aren't. It's the same principle as a flywheel coming apart in an old engine too. Everything's holding back a lot of force until it doesn't.