What am I missing? Or am I?

Ok, trying to alter a design and I’m using std 201 bit. I want a .250 hole. Is it possible? or must I use an eighth inch bit? I understand there will be a slight bit of slop, but will CC not drill straight down? If I put in no offset, then I’ll have a way bigger hole. Inside shows empty toolpath.
I tried fooling it a bit by adding a bit that was .247 but no go.

Tell me the answer please?

Cnc machines do not drill very well. Trying to make a 1/4 inch hole with a 1/4 inch end mill will not be pretty. Yes use a smaller bit.


yeah, I know that. I just was really wondering if software prevented it.

The software will not go where it is smaller than the bit. I just created a project with a .250in hole and a .252in hole and the first did not cut in the simulation.

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Others may know the internals of cc but I was trying to make fillets on a project. Usually you use the radius which is half of diameter. Until I set the diameter dimension larger the fillets would not show up in the preview. So I assume if a dimension that cc did not agree with cc would not allow it.

Guideline is smallest feature 10% larger than endmill, so the smallest hole a #201 will cut ought to be 0.275".

thanks for the information