My surface finish went from rough to mirror smooth after I switched to a 0.5mm corner radius tool

I was running a job on 6061 aluminum for a customer, making some small brackets. The finish on the vertical walls was always a bit streaky, no matter how I tweaked the speeds and feeds. This went on for about two weeks. I was using a standard 3-flute flat end mill. On a whim, I swapped to a tool with a 0.5mm corner radius, kept everything else the same. The difference was instant on the next part. The tool just seemed to slice through the material cleaner, leaving a finish that almost looked polished. I think the small radius helps distribute the cutting force and reduces chatter. It's now my go-to for finishing passes on aluminum. Has anyone else found a specific tool geometry that made a huge difference like this?

3 comments

3 Comments

ivan_mason8d ago

Dude, I feel this so hard. I was fighting a nasty chatter on some delrin parts for ages. Switched from a sharp corner to a tiny radius like yours and bam, problem gone. It's wild how such a small change can make the cut feel so much smoother. That lightbulb moment when the first perfect part comes off is the best.

johnson.paul8d ago

Always thought sharp tools were best, but @theac63 is right, that tiny radius really does change everything.

theac638d ago

Oh man, that's the best feeling! I had the exact same thing happen on some stainless steel pockets. I was using a sharp tool and getting this awful, torn look. Switched to a tool with just a little corner radius and it was like night and day. The finish went from looking scratched to almost glossy. It just glides through the cut, doesn't it? That tiny bit of rounding makes all the difference.