[DavidhCNC]

I want to use a ballnose (or ballmill) end mill to mill a groove into a part for a tube. So far, we have avoided using the end mills because of the small line the ballnose end mills leave inside the groove in the center. I believe the end mills that we have are all center cutting. Will a non-center cutting ballnose end mill leave a nice smooth finish without any lines?

[diamond.3211]

The reason that you are getting the line in the center of the groove is that even though the ballmill is centercutting, the cutting speed of a ballmill acts the same as a drill, i.e. it decreases as it approaches the center of the cutter until it is zero at the exact center, so the line that it is leaving is material that is being rubbed instead of cut.
If you can find a cutter that has even a slight flat instead of a true ball, that could potentially solve the problem, or just polish the line out of the part.

[easymike29]

Can you tilt the cutter at an angle instead of vertically?

Gene

[DavidhCNC]

Hmmm, well, I would need to make a jig that would hold the piece at an angle...

Thanks for your help guys