I noticed today our Daewoo Puma 400 with Fanuc 21Ti control was running way too fast on large dia. parts, I was turning some 18.5" dia. wear rings made from super duplex and was wanting to turn 125 surface feet per min. that should be about 26 RPM, however the machine was running 50 RPM at 18.5 Dia. with a G96 S125 speed command??? The funny thing is if you manually move the tool down in X after starting the program the speed would remain at 50 RPM until the tool reached about 10" then the chuck would start increasing speed and at that point it would have the correct RPM for the dia. it was at. The only way I could make the parts was to use a G97 code to force 26 RPM. I think it may be a parameter issue?