# Simple Math - Tolerances

I want to cut a path that is 1/8" wide using a 1/8" mill. Is that possible with a 1/8" mill, with the add of “Tolerance”, and “Machining Margin”, “Stock to Leave”. Using a 1/8" mill, how wide would my path need to be with a tolerance of .01, a machining margin of .1375, and stock to leave of .01.

Thanks in advance for clarification and education.

Before you can do the math, it’s best to evaluate the effective cutting diameter: http://docs.carbide3d.com/article/47-measuring-runout

I want to cut a path that is 1/8" wide using a 1/8" mill. Is that possible with a 1/8" mill, with the add of “Tolerance”, and “Machining Margin”, “Stock to Leave”. Using a 1/8" mill, how wide would my path need to be with a tolerance of .01, a machining margin of .1375, and stock to leave of .01.

In short, the answer is no. A good rule of thumb is that with MeshCAM, the smallest feature one can machine is 10% larger than the diameter of the end mill.

The machining tolerance should always be 0.0001. Let MeshCAM crunch! It takes longer to compute but shorter to machine.

A stock to leave of 0.01 would add 0.02 to 0.125 - 0.145. No way to cut anything smaller than that.

See this Forum discussion for a discussion how fine a feature MeshCAM can handle:

mark