Monday, September 28, 2020

When Self-Centering 3-Jaw Chucks Stop Holding the Workpiece

 What does that mean.  I am sure that I used to be able to cut aluminum tubing.  Now, even at .002" runout, the tube (2.5" long, 1.5" OD) just keeps popping out when I try to square it.  I am sure that this used to work for me.  I tried a new cutter.  I tried sandpaper between jaws and tube.  Nothing is working!


  1. Jaw faces might not be parallel with each other. Splayed?

  2. not a machinist but have you tried reinforcing the inside of the tube? In the past how much was left inside the 3 jaw chuck. try as much tubing as possible inside a 3 or 4 jaw chuck. The only reason I responded is that no one else even suggested anything and you didn't indicate you figured it out.

  3. W: Good thing to check.

    augustrr: As deep in the jaws it will go.