If somebody could manufacture a drill that would hold a +/- .0001"
diameter and location tolerance they would become very rich. Every
manufacturer would buy them to avoid second operations like reaming,
boring, honing, grinding. With a good setup and drill I've seen them
hold a +/- .0005" tolerance. Then again I work on vertical machining
centers not drill presses. I still don’t expect to hold that so
I make the holes under and do the secondary operation. I've never used
a drill like a reamer. I prefer endmills or boring bars.


Jeff