[rcs60]

I hadn't thought much about this subject until reviewing some else's program
normally i would use the same feed rates on the x axis as i used on the z axis
the print calls for a 32 micro on the face of the part and this program uses .010ipr for the facing cut .0312 radius insert
if i use .01 in a ipr to microinches this comes out to 134microinches
if when programming the .010 ipr because this is diametrical would the feed rate be .005 compared to a z axis feed rate ?
if this is the case the the microinches would drop to 33 microinches

[vw_chuck]

No the thing that is changing on the x axis is the SFPM. As you get closer to center you SFPM drops to zero. What you would want to do is keep constant SFPM if you lathe can do that sort of thing.

[deadlykitten]

hy i also looked into this a while ago, trying to figure out the time needed to cut a face with g96; i just run a few trials to figure out if feed is full or halved, etc

things may change for y lathes

as for roughness, once you do the math, in reality you could go faster, because, if you use the calculated feed, then real roughness will be way better than expected; thus you can obtain a desired roughness at a feed > estimation, because, in reality, some plastic deformation occurs during turning, that will smooth out the surface. If you have an inhouse rugozimeter, then adjust as you go / kindly