[Xenomorph]

I need to machine some 1" holes on my CNC and I was just going to use a 1/2" end mill but the blue print requires .0005" TIR. Should I be able to expect to hold this tolerance just by circular interpolating the hole or should I do something else?

[quadbob]

Unless the machine is really new, that kind of tolerance is difficult to maintain. Boring is the way I would go. The hole will be round rather than machined in quadrants. It really depends on the ways of the machine.

[charger19690]

I agree.....0005" is pretty close on most machines. If it were 1 part I have done, just re-running it and basically rubbing the size it, but I would boring is the way to go.

Mike in MN
http://www.cncbasics.com
http://www.cncbasicsforum.com

[Mcgyver]

boring is more accurate than interpolating buy to split hairs is suppose it would depend on the machine wether interpolation would hold the tolerance. btw, its better if you put a subject line that has some meaning

[varga]

you could interpolate it to about .003 undersize then ream it to size... although a reamer that size would cost quite a bit

[RICHARD ZASTROW]

Drill undersize and ream with a jig borerer (end cutting, no chamfer) reamer?

Dick Z

[Xenomorph]

All, thanks for all the help. I guess I will plan on boring it.