ISB 3/32’’ Carbide Square Nose End Mill Set, 4 Flute Micro Grain Carbide End Mill Bits for Alloy Steels/Hardened Steels/Aluminum/Copper, Suitable for DIYers and Professionals, 5 Pcs

I go through a LOT of these smaller end mills on hardened carbon steel, and they always cut through even hardened high carbon steel, as long as you don’t force a cut with them they work great, but if you try and take too big a bite or feed too fast they will snap like a pretzel, but that’s the nature of solid carbide bits, you need to take your time, have your feed and speed and depth just right and if you do then these will last a long time

I was in a pinch for 1/16 endmills, decided to buy some cheapies with fast shipping. Ran a complicated 4th axis part, extended quite a ways with no tailstock, had it do a full 360 degrees of finishing on 4140 tool steel, including plunging across steps (roughed from a 1/8 bullnose) and the first try it held up great, I then used the same tool to do some deep (.125) pockets, and a little cleanup with some 3d passes, tool still looks great. I am a pro machinist btw... I usually run Harvey, kennametal, sgs, etc... I am real happy with these.

Cuts Cleanly and accurately

Worked well for my project. Sharp, strong for brass notching.

These are great bits. They aren’t too expensive. I used them to cut a channel in some 6061 Aluminum to install an ambidextrous bolt catch on my hunting rifle. It cut through the aluminum like butter, add a few drops of lubricant and you can mill to your desire. Fortunately they are cheap enough that they're basically disposable.