[BROCD]

Does anyone have a good idea of how to hold a 32 finish at the bottom of a 1.12"L x .96"W X .695 deep pocket? Right now I'm making a .012" skim cut (ramp in,ramp out) pass at bottom of pocket but still get small swirls on the surface. We are currently using a .50" Carboloy Mini Master to do this operation.

Material: 4140 Rc 28-32
SFM: 450
IPR: .003

[NC Cams]

More cutter teeth and slow down you feed rate about 25% to roughly 1" minute, do final cut at 0.005" and 0.000" spring pass cut after the 0.012". We do something like this with our masters when we cut them and they look nearly ground.

I'd be more interested in knowing HOW WOULD YOU MEASURE the surface finish outside of visually???. If the swirl marks are recessed as opposed to protruding, I'd think that they are inconsequential to performance outside of visual discontinuity. Then again, if that is what the customer wants............

A 32 micro is a bit too smooth for a sleeve bearing (40 to 60 is optimum) but quite adequate for a ball bearing.

[BROCD]

Thanks NC I'll give this a try. As to your ? about checking the finish,occasionally we have to cut pocket open or do test cuts in scrap material.
I would be interested to know of anyone knows of an economical way to check the surface at the bottom of a .695 deep pocket.

[NC Cams]

To nondestructively test the surface of a cylinder bore of an engine, piston ring makers have this plastic tape/thingie/material that they apply to the surface. It comfoms to the surface and replicates the as-honed surface.

They then peel it off once it hardens/sets and do surface finish trace analysis for finish, platteau, torn metal, voids, etc. Don't know what it is called or where to get it but it does exist.

Might work for what you want to do....