Dave wrote on 01/20/17 at 07:09:06:(I really hate it when the drill bit grabs the thin sheet metal and throws it across the room).
One thing my Dad taught me when I was a kid: NEVER raise the quill if the drill bit catches the part and slings it around as it could send it flying across the room - and sheet metal makes a nice flying knife!
The other thing I learned from an old machinist (this was back in 1974 so I am the old one now!) is to put a little "flat" on each cutting edge of a drill bit and it will prevent the grabbing that happens on sheet metal. And it also prevents the three-sided hole!
One day in a machine shop, I had to drill a ton of 1/4" holes in pieces of brass. I got a brand new drill, and it barely would drill w/o a ton of pressure. This old guy (who also had some "shakes" came by, and saw me having trouble. He took my new drill, went over to a bench grinder, and, even with some shaking, put these little flats on the cutting edges. I thought this was a joke, and this couldn't possibly work. WOW! When I started drilling again, it cut the brass like butter!
A few years later in Tool & Die classes, I found out from at textbook the very technique that old fella taught me! It also works on other types of metal (like bronze and aluminum brass) AND, guess what? Sheet metal!