I am going to be attempting to gun drill a 1mm (0.0394'') diameter hole 3.1" deep. The material is 440A and the gun drill is solid carbide. I have a descent experience with gun drilling on this machine but I have not attempted a hole this small in diameter. The machine is a Citizen M3-20 with Y-axis on the turret. The hole is 78.74x the diameter. I can supply 2000psi of high pressure which should be plenty considering that tiny through-hole can't flow very much. The only thing I can not achieve per drill manufacturer is the sfm. A recommended 125sfm puts my main spindle at 12k rpm. My spindle max speed is only 10k. Feeding at .00014 ipm. I am feeding out of the guide bushing, gun drilling with my turret. Positioning the gun drill about 0.100" from the face of the guide bushing and feeding the material over the gun drill which is stationary. Just wondering what to expect out of a such a small gun drill? I had a little bit of difficulty with an 0.061 but at the end of the project I had it dialed in and running successfully.