Gene, 0.091" (=2,3 mm) would be perfectly in the DIN / ISO range. I use 2.4 mm for easy working if strength is not the issue. More, my drills are all produced a little under their nominal size, maybe a few hundreths, to allow for de-centering of the cutting blades in order to give a correct result when the hole is done. Admittedly, it's not easy to keep that up when re-sharpening by hand... In order to reduce the cutting forces and risk of breakage, all hand tap drills come in sets of three beginning with a straiht tip with drill blades to make sure the hole is not too small and keep the threads perpendicular to the surface. Peter
Am 23.01.2016 18:27, schrieb Gene Heskett: > On > Now we are getting more precise than we can drill with the typical drill > bit, which usually drills oversize because the tip flats are > un-avoidably off center. Even to a small extent for pricy carbide bits > in the smaller sizes. Yesterdays finished tapping looked great, but I > think I could have used the next larger #drill. Yeah, my back of a > napkin said a .089 drill, kcalc says 0.0984251968503937008 for a 3mm.5 > screw. > > No wonder I felt like I should peck it, the hole WAS too small. > > Cheers, Gene Heskett --- Diese E-Mail wurde von Avast Antivirus-Software auf Viren geprüft. http://www.avast.com ------------------------------------------------------------------------------ Site24x7 APM Insight: Get Deep Visibility into Application Performance APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month Monitor end-to-end web transactions and take corrective actions now Troubleshoot faster and improve end-user experience. Signup Now! http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
