If you also intend to make knives, then a drill press is just about imperative. I know; I ruined several blades when I first started by drilling various holes off center. When you go to slide a pin through two layers of scales, plus the tang, those holes had best line up properly or you're in trouble. For drilling any type of soft(untreated) steel, be it stainless or carbon, just about any type of drill will work. I use HSS bits mainly because they last longer. For this type of drilling slow speed(my drillpress runs at 540 rpm at it's lowest setting) and cutting oil work fine. You can drill without the cutting oil at slow speeds, but your drill bit life gets short.
For hardened steel you can use carbide drills, masonary drills, or glass drills. I only have one carbide drill, 1/8" spade tipped, and rarely use it; which is why I still have it. ONLY spade tipped drills work properly/last when cutting knife metals. They are properly used at high speeds(varies with the bit) and a lot of oil. But they are fragile. They are also limited in depth. My 1/8" drill is not recommended for drilling more than twice it's diameter; since I never use a steel thicker than 1/8" that works for me. Given a choice between masonary or glass drilling bits(both of which are carbide tipped), the glass bits are better shaped, and usually more precisely made. As someone in one of the posts pointed out, you are essentially grinding through the metal rather than drilling. You can find them at True Value or Lowe's.
I learned a long time ago from a guy named Bob Engnath to use Number and Letter drills rather than standard sizes in knifemaking. Trying to fit a 1/8" pin through a 1/8" hole can be downright frustrating. If the pin is even microscopically larger than the hole, it gets even more trying...especially if you want to use softer pins like copper or copper mosaics; or are using a fairly soft/fragile handle material...it will crack if you're not careful. Ruined a few handles that way. There are presses you can buy that will do it much better than using a hammer, but they can run into bucks.
Number/Letter drills tend to be slightly larger in diameter than standard ones. I use a #30 for 1/8" holes(two thousandths larger) and an "F" drill for 1/4" holes(.257). I personally would rather fit a pin covered with epoxy or super glue into a hole than press/pound one in. The trouble with peening pins is that if you peen too much you create a lot of permanent stress between the pin and the handle material..i.e. the pin keeps "pushing" against the material since by peening too much it needs to expand. Eventually the pin usually wins and you end up with cracks around the holes. Might take a while, but it WILL happen; how long depends on the hardness of the scales and how much pressure you've created by over expanding the pin. When using the slightly larger diameter number/letter drills to make your holes, the slight difference between the smaller pin and the very slightly larger hole disappears when you finish the handle, since when you sand the pins/bolts you get an effect called "smearing". You can't even tell. I used to be able to buy number/letter drills around here, but that "old fashioned" hardware store closed, and now I order them from the Knifemaking supply houses. Sheffields and Jantz carry them; I'm sure others do also
Poll