I finally blew a tool holder clean off the spindle last Tuesday

I was running a 3/4 rougher in a CAT40 holder at 10,000 RPM and 200 IPM on a piece of 4140. I had tightened the pull stud but I guess I didn't torque it right. The whole holder flew off and smacked the chip auger housing so hard it left a dent. Has anyone else had a pull stud come loose like that and did you find a better way to check it before hitting cycle start?

2 comments

2 Comments

the_jana1mo ago

A buddy of mine had a CAT40 pull stud snap and the holder went clean through a coolant tank.

lee.diana1mo ago

Did you check the pull stud's shoulder for wear before you installed it? I had a holder come loose on a older Haas once... turned out the stud was slightly mushroomed from a previous crash and it didn't seat right in the drawbar fingers. We had a guy who'd just tap the pull studs with a hammer to seat them in the holder, and half the time they'd get a little bent too. Ended up finding a few of them in a bucket that looked like they'd been chewed on by a dog.