Quesation on cnc for cutting angles

[Bob Coates]

Knowing nothing about what a cnc can do but a friend offered to cut some wedge templets for me and I was wondering how accurate of a angle they can make.
The templates would be used to cut wedges for 28, 37, 38, and 39 pieces rings. My guess that 3 decimal places would be ok.
I have made others using trig and radial arm saw to cut, then fine tune, but was hopping his cnc cuts would be good on first try.

Thanks
Bob

[Jim Becker]

The CNC machine is capable of "splitting hairs" when it comes to accuracy. As long as the person creating the CAD/CAM is accurate in their drawing and they have a quality machine that doesn't deflect when cutting, the angle will be exactly as specified.

[John TenEyck]

The accuracy of the angles I've cut are as good as any means I have of measuring them. I've made 12 sided rings that close up w/o visible gaps. The problem I had was the cut edges weren't square until I figured out the right combination of bit style and cutting parameters. Once I had that in hand, perfection.

John

[Michael Burnside]

Most CNCs worth their salt range from 0.005 down to 0.001 repeatability. Mine specifies 0.001 and I can attest that in my experience measuring and empirically, it is well within that tolerance. This assumes no pilot error in chip load and selecting the proper bit. If I CNC a 90-degree cut, it's 90-degrees, same goes for 45, etc. If I were using these templates for measuring, I would be sure to use plexiglass, aluminum or at least 13 ply birch/MDF because the wood movement is probably the area where accuracy will suffer, not in the CNC.