Unwanted overcutting advice please

[grim_d]

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.

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.

[m_c]

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.



Noted regarding the radiuses, thank you for the information. Shouldn't V-carve handle that though?

I've never personally used V-carve so can't comment, but I'd normally design the parts with suitable radiuses or select the cutter to avoid radii matching.
I can't remember the last time I had to machine an internal sharp corner, so I can't even think how my usual choice of F360 handles it, but I'm sure there will be a setting somewhere.

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.

R&P can work if designed well, and you're not expecting micron tolerances.
Other options are rotating ball nuts, supported ball screws, high pitch ball screws.
There's not really an ideal solution, but as with most things, it can be done if you select the correct components.

But I hate to tell you, you can probably buy your machine on Aliexpress, if not, Alibaba.
I looked at a 4x4 machine, and there are some compelling options, but they're all built to a price.

It's a shame Jazz isn't about, as he's the one who really knows about Routers (I'm more metal working, than wood bothering!)