Hello, I have a Tormach 770 and there's a part I'm making where I need to drill a 1mm diameter hole at maybe 5x diameter depth. Part is aluminum. I was using some carbide drills off McMaster and I got through 1 part OK, but snapped both the drills I had ordered on the next one.

I was using G-Wizard feeds and speeds of 10000 RPM and 93.1 mm/min feed with coolant flood.

I was wondering what is the smallest hole you've been able to drill on a Tormach? I was thinking maybe some nice TiB2 coated Harvey Tool drills could get me through the job, I can't really see what's happening but I imagine edge buildup on the drill is a part of it. But maybe the rigidity and runout of the Tormach just won't allow micro-drilling?

Edit: I was using the ER20 TTS toolholders. Last I measured runout I was getting under 0.0005" on the TTS holder and about 0.001" on a short 1/4" endmill tool tip.

Thanks