I am trying to run a program with a 2in radius leadin on one of our robo drills with 16i-M control and am having an issue. The arc is on a plane that is tilted 45 degrees from the xy plane, so the 2 inch radius arc is a three axis move. The geometry is different from a true helix so helical interpolation wont work (tried it). The current program is short line segments, but the machine is having a hard time running it. Instead of running smoothly through the code it shudders, stopping at the end of every block of code. The tool path looks good, but as you can imagine this finish is less than acceptable. I added a G64, cutting mode, and that didn't help. I also tried using the G08 look ahead, that didn't make a difference either. I tried te G05 and G05.1 but they are not turned on. Does anybody have any ideas on how i can get a smooth cut out of this machine? Would it be worth buying the G05 or G05.1 options? In the manual it looks like some additional hardware would be necessary for the G05/G05.1. I would appreciate any help that anybody can offer.