A good drill press, part 2:back gear and morse taper.
I’ve talked before about the characteristics to look for in a good metal working drill press, here’s a couple more. A good drill press should have the chuck mounted on a morse taper shank. This allows you to have several chucks and switch between them, say, a big one so you can use 5/8″ or 3/4″ shank drills and a nice small accurate one for very small drills. It also allows you to use drills with morse taper shanks:
In addition, other cutting tools can have morse taper shanks (end mills, flycutters…) and special morse taper holders are availible for things like center drills, taps and dies.
The other thing a good drill press should have is either “back gears” or a third pulley sheave, this lets you use large diameter drill bits. Just because you can chuck up a 1″ silver and demming (1/2″ reduced shank) bit doesn’t mean you can successfully drill with it. Large bits need to be turned slowly or they will burn up, holesaws are even worse.
With only two sheaves I’d only be able to vary the speed from ~700 to 2000 rpm, but with three I can go from 250 to 3100 rpm
My grandfather (an old world trained tool and die maker) claimed that a large (over 1″) bit should be turned slowly enough that the outside of the flutes are not blurred when you look at it.
