Thread: GAR Micro finish comparator

Recently started taking in a few outside jobs that surface finish call outs on the prints. Pulled out the old Gar specimen instructions sheet and was perplexed by a couple of items.

1. Turning: For a 32 finish the feed would be .002" (assume that is IPR) but doesn't specify a tool nose radius?

2. Milling: There's a block for side milled, end milled or profiled then one for milled with periphery of cutter. How do they differ? How do you calculate the feed?

Obviously the scratch test is the final word but just couldn't get my head around the rest.



Sorry couldn't figure out how to rotate the pic.

One thing I have done is to use a USB microscope to take a picture of the sample then take a picture of the finished part and compare them on the screen. With the magnification I figure it should be pretty easy to see if the lines match up or not.

I actually now have a surface profilometer, I just have to get it fixed...

Charles