CNC Equipment and Tooling recommendations

[Gray Adams]

Originally Posted by Jared

The tormach is actually quite accurate. We can hold +/- 0.0003” on circular features. It’s easier to get within .001”, which is adequate for a bearing.

That sounds absurdly tight for helical interpolation on anything but the higher class Japanese machines. How are you even measuring that kind of tolerance? Even if you could hold that kind of tolerance, with the thermal expansion of aluminum, holding a part with a 1.250" hole in it in your hand for a few minutes will cause the diameter to grow .00033 in.

Anything even close to that tight should be done with a boring head or reamer anyway.