fwiw

I use 80 degree positive rake inserts, with an extreme hi positive on top,
specifically for non-ferrous metals.

ccmt 2xx

ccmt 3xx


"Richard J Kinch" wrote in message
. ..
HeffaLump writes:

The circles are easy to see but impossibly difficult to photo, you have
to catch the light just right but they appear to be 2-3mm apart. I
cannot tell if they are truly concentric or spiralling.

I second the suspicion about the cutting tool and/or coolant, rather than
the rigidity. Sounds more like a finish problem than a positioning
problem.