I sorry for bump an old topic I just have a few interesting observations from personal experience, maybe someone will need this information in the future.Stainless is already pretty hard and as it heats up it will work-harden even more. Hal has it right, go to a real industrial/machine supply house and buy some good quality HSS/Carbide twisted drill bits. If this is a one-time thing then don't bother getting coated bits. The coating is primarily to help the longevity of the bit, not really to ease or help the drilling process itself. If you plan to use this drill a lot then an AlTiN coating works good on extremely hard metals (steels, stainless, high-carbon, etc).
I would probably use a 1/8, then 1/4, then 3/8, then 1/2" to get the desired hole. You could also stop at 3/8 if you wanted to use the punch listed earlier in this thread. The smaller bits you can spin faster (200-ish RPM's), then slow down as you drill bigger (100-ish RPM's). Trick here is to limit the linear speed of the cutting surfaces so as to not work-harden the stainless (overheat). Ask the supply house for a drilling fluid that isn't runny and put a quarter-sized blob over the cutting area. When one bit drills through it, change the bit then wipe the new bit down with cutting fluid using a rag. If the steel scarf (shavings) start to turn blue as you are drilling then you are going too fast and should slow down. The stainless you are drilling is thin and will heat up quickly if you aren't careful. If you do blue the stainless then stop, let everything cool down (bit included), re-oil, and SLOWLY drill past the blue.
The last thing I want to mention is to not break these bits
https://mechanicguides.com/best-cobalt-drill-bit-sets/ while drilling. Unlike the cheaper bits these do not flex. What they will do instead is shatter if you use too much force or dont hold the drill steady.
Hope that helps!
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