Switched from HSS to carbide endmills for aluminum and holy smokes

I was running HSS for like 2 years on my little Haas and kept fighting with tool wear and chatter. Tried a 3 flute carbide endmill last week at 12k rpm and the finish was night and day better, cut time dropped by 40%. Anyone else make the swap and see huge gains?

2 comments

2 Comments

margaret991mo ago

That 40% time drop probably hides something nobody's mentioning. The real gain isn't just speed. It's rigidity. Your Haas at 12k rpm with carbide makes the tool stiffer than HSS ever could. So you can push feed rates way harder without chatter. I saw a guy go from 50 inches a minute to 120 on a simple pocket. That's where the real savings live. Not the rpm. The feed. Check your chip thinning too. Carbide lets you take a heavier radial cut so your tool actually engages steel instead of rubbing aluminum to death.

shane_williams1mo ago

12k rpm? Man, my little Tormach can barely get past 7k before it sounds like a dying lawnmower. I'd probably need earplugs and a tetanus shot just to stand near that thing spinning that fast. That said, the cut time drop makes sense though. Carbide is just a whole different animal for aluminum. I tried a 3 flute once on a test piece and the chips came off so clean I thought I'd accidentally hit the wrong tool number. Was genuinely confused for a second. But 40% is wild. That's basically a free coffee break every few parts. Might have to save up for a proper spindle one of these days, my HSS setup is starting to feel like I'm cutting with a butter knife.