Where are you located? I have used a hole saw on a drill press and was amazed how well it cut. If you have access to 1 it will blast through it.
I've cut 8 32mm holes through 10mm stainless plate and using right technique and fluid, hardly even put any wear on the holesaw.
I use them everyday at work on various material and got to say pay for decent ones. They will be so much better than cheap. Sutton are a good start. Milwaukee ones seem to be ok but I have a kit which is called reload. Has quick change setup and has been great. I've only just recently broke the 20mm and it's about 7 years old
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