MIMF

Craig Bumgarner wrote:

David King wrote:I have a lot of dead carbide endmills that have super smooth polished shanks. I wonder if 1/4", 3/8" or 1/2" dia would work best?

I doubt the diameter of the burnisher matters much, it is going to be point contact no matter what isn't it?

It is point contact until the edge starts to roll, then you get a contact area. I think a smaller diameter will roll the edge over more quickly but possibly be harder to control. The smaller diameter will equate to more pressure with the same force applied to the tool. Pressure = force/area.

A smaller diameter burnisher will stretch the burr more as it is rolled over because it is a smaller diameter. The larger diameter burnisher rolls the burr more gradually because it has a slightly larger contact area. By stretching the burr it tends to crack and become a bit ragged, and leaves ridges in your material. This doesn't sound too coherent as I re read it but it is true.

I really like the ultimate scrapers from StewMac (Al Carruth's version).
http://www.stewmac.com/Luthier_Tools/Ty ... raper.html