This is the tap I am using: http://www.mscdirect.com/product/details/58607482?rItem=58607482 The drill I am using is 10.5mm which is 0.875 of 12mm so I would say that seems fairly large. The OSG online tool recommends a 27/64” (10.7mm) drill, so I am very close (0.008” difference). Also, if I was using OSG's tap they recommend 23.8764 IPM which equates to a spindle speed of 400 RPM. I can try that (I used 300 RPM), but I suspect I am going to have the same (torque) issue I had before. And perhaps the answer is I just don’t have enough torque at low spindle speeds to do it in one pass…
-Tom > On Jan 22, 2016, at 12:00 PM, John Thornton <j...@gnipsel.com> wrote: > > What kind of tap did you use? I use only ElectroLube coated taps from > OSG. OSG has an online tool to select the correct tap and drill for each > job. I once had to deep hole tap in some 7075 and my normal taps broke > off. I used the tool and got the right tap and drill so the hole size > was correct for the job. Tapping charts usually use 75% thread depth > which is usually OK for a depth = diameter, for deeper depths you need a > bigger hole. > > JT ------------------------------------------------------------------------------ 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
