Cutting Chatter When Precision Boring

I just came across what looks like a great blog from Criterion, the boring head people. They had a great tip to reduce chatter: make sure your depth of cut is greater than the radius on your cutter. It makes sense, and should apply when turning too. Here is how they explain it.

Consider the cutting forces when the insert is cutting less than the radius:

See how the forces (arrows) are largely trying to push the insert out of the cut?

With a deeper cut, there are more arrows acting to stabilize the forces so they’re not all trying to get the insert to deflect and skip over the cut.

The result is a better finish and less likelihood of chatter. Having to increase depth of cut in this situation is just one of the many counter-intuitive situations we encounter when machining!

Related posts:

1. More Shaper Tricks on a CNC Mill: Cutting Splines
2. Clever Thread Cutting Gadget