Lathe Steady Rest Safety

[rake60]

I had a couple wake up calls at work today while turning parts with the steady rest engaged.
Nothing new, it's happened before, but it did make me think about it again.

The stock was 2-1/2" CFA 4140 Alloy Steel. It had a slight warp to it.
The CNC I run will attempt to maintain the surface speed you program it to cut at up to the
maximum speed you set. The maximum speed was set at 1200RPM.
As the tool was facing the part the warp in the material caused the stock to "walk" out of the
chuck. As it walked out the cut got heavier until it broke the tool. At 1200RPM that all
happens very quickly. Three time in one shift!

Most of us will never run that speed at home, but bent stock or a steady rest set to center above
the chuck center will cause the same "walking" effect.

If a piece walks out at 600RPM and hits a jaw on the chuck things get ugly.

Rick

 

[Philjoe5]

Thanks for the message Rick. I often use a steady rest and it's worthwhile to know all the things that can go wrong. Glad to hear no one was on the business end of it.

Cheers,
Phil