10pcs 0.8-3mm Titanium Coated Engraving Milling Cutter Carbide Bits, 1/8'' Shank for Dremel Rotary Tools by YEEZUGO

I used these with a rotary tool to cut slots in a PCB. Like a hot knife through butter. Also touched up an aluminum casting and it cut easily. Tip: turn your speed down. The small bits seemed to cut cleaner around 70-80% max RPMs

works well

These can work through welded steel. As in small bolts welded in exhaust baffles.

bought to cut welds off, not at all for this purpose, did not cut hardened welds, skipped, broke, stuck, dangerous in a dremel tool, for other purposes possibly useful but did not help me at all. tips broke on contact

They didn't burst into flames when I used them, though to be fair, that's never happened to me before with anything that wasn't already naturally flammable anyways. Needed it for a project (Dremel) and it worked better than expected. I was kidding about everybody needing to own a set. Only buy one if you can use them in a device that can use them, like a Dremel or a mill. If you buy them for a different reason, then you may be disappointed in their performance.