11-04-2012, 01:06 PM
316 is pretty hard on drills. You will end up sharpening whatever you use quite a bit on 150-180 holes. Cobalt will help. If you're freehanding, carbide drills will break too easily. BUT, I have successfully taken a carbide tipped masonry drill and sharpened it for metal use and had good success. You just have to keep them cool enough not to melt out the braze. Low speed, high feed.