I have a 3/8 hand-held drill and that's pretty much all I need for my projects. But now I have a project where I have to insert large dowels, and they will need a 7/16" hole. I don't have that size bit, but before I rush out and buy one only to find that it won't fit my 3/8" drill, I want to know if there are adaptors or other tricks I can use to make it fit.
There are bits with shanks ground down to 1/4", 3/8", 1/2" dimeters to fit chucks. They may need to be special ordered and may be expensive. I have several but I inherited a bunch of bits so I don't know what they cost. I have also ground 3 flats on shanks when they were a little too large for the chuck ( assuming you have a 3 nib(?) chuck).