If you go into the Tool Dept of like Home Depot, hole saws are the round, toothy cups that you mount to a mandrel which fits into a drill or drill press. If you can envision this thin metal cup that has teeth on the bottom edge, and when it is spinning it cuts a hole into the steel, or wood, or whatever. They use them in home construction to cut door handle holes in doors.

The ones you want are bi-metal, and are made to cut steel. Stainless is a different animal, and I have never used one on it, so can't say how it will cut. The first thing you do is drill a small pilot hole in the center of where you want the hole to end up. The mandrel is made so you can interchange and use various size holesaws on the same one. It also has a long drill bit in the center that you begin by drilling down through the pilot hole you made. Then the cup contacts the metal and begins cutting the hole. Go slow and use lots of lubricant. Clamp the work to the drillpress, because a 3 inch saw will want to spin the part.

I think what is confusing you is the term hole saw. It is just a big cutting bit that spins and cuts a circle shaped hole. Hope this explanation helps.


Don