Quote Originally Posted by Lee Roberts View Post
Ok, try the same settings again but this time actually make the internal corners radiused (filleted) for the 2mm cutter, a 1mm radius should be great. I would then say its a hardware issue if the problem persists.
Ok I'll give this a try. To be completely honest I think it may have been tool deflection in my example as I cut something yesterday with a shorter cutter in a smaller diameter which worked out absolutely fine.

I'm used to using bigger cutters on metal so deflection isn't quite as much of an issues, carbide has far more flex in it than I expected.

I do plan on doing some more experiments but getting the time is extremely difficult.

Quote Originally Posted by m_c View Post
You really don't want to be machining radiuses that match the cutter radius.
Even on extremely rigid machines, it's bad practise, as you're likely to run into chip clearance and resonance issues.

As for the machine, anything with rack and pinion, is never going to be the most precise of machines.
Noted regarding the radiuses, thank you for the information. Shouldn't V-carve handle that though?

Regarding the helical rack and pinion, what's the other option for larger machines? (Not necessarily mine), as I understand it ballscrews run into vibration and whipping issues at longer lengths?

Just curious for if I get a bigger machine in future.

I understand it's not a high end machine, but similarly it's not a wet noodle from AliExpress, it certainly seems like it should be capable of holding the tolerances I desire....operator error aside.

The next league up of machine is well into the tens of thousands, unjustifiable currently.