Vent: People keep using the wrong speeds for aluminum and it drives me nuts

I swear every other day I see someone on here complaining about their finish on 6061 and then they post their settings and they're running like 8000 rpm with a 1/2" endmill. I mean come on. That's gonna load up and chatter every time. I learned this the hard way after ruining 3 parts in a row back in 2021 at my old shop in Cleveland. Spindle load was all over the place. Dropped the rpm to 5500 and bumped the feed up and it cut like butter. Has anyone else noticed how many guys just guess on feeds and speeds instead of looking at the chip load chart?

3 comments

3 Comments

milessmith17d ago

And thats the thing, most guys just crank the rpm up thinking more speed equals better finish but they forget about actual chip load. I remember when I first started I did the exact same thing, thought I was being smart but just ended up with a bunch of scrap. Once I started actually doing the math and dropping rpm while bumping feed it all made sense. So many people skip that step and then wonder why their aluminum looks like sandpaper.

james_campbell1217d ago

Yeah man, I've been there too, nothing worse than ruining good aluminum cause you skipped the math.

grace_wright17d ago

Miles, I gotta push back a little on that, no disrespect. In my experience with aluminum, cranking the rpm and keeping feed light actually gives you a better finish on thinner walls, especially with 6061. Too much chip load on a delicate part and you'll push the material around and get chatter. @james_campbell12 might back me up that it depends on the setup too, like if you've got a rigid vise and a short stickout, sure, bump the feed, but for anything flimsy I'd rather spin fast and take light passes. Just saying, there's more than one way to skin this cat.