I have no engineering knowledge and must admit I don’t know what a lip & spur drill that Neil used is. However I asked my daughter for two Colt pen drills ( 25/64 & 15/32) for the baron pens. I want to start drilling and don’t stop until the drill comes out the other end without any break out of the blank, thus the request for the Colt drills as a Xmas present.
She gave me a Colt 25/64” but a Fisch 15/32” and I didn’t know how the Fisch would perform. Today I drilled two barons, an olive wood and an acrylic blank. Both drilled at 2000 revs and both went straight through without stopping and no break out. I know they are expensive but without any understanding of drills and how they work I want a one stop shop and these appear to be it.