Posted by Bills on November 11, 2009 at 10:19:11:
In Reply to: Re: Finish problem 6A Fellows shaper posted by Sean on November 11, 2009 at 09:59:26:
It seems to me that a sharp cutter with the normal amount of positive rake, and a good flood of cutting oil should work. When you say "tearing" do you mean that small chumks are breaking out of the exit tooth space edge, or is it more like a smooth smearing of material causing a bur? I think that annealed material, depending on how soft it is, is likely to form plastic burrs. The T6 is a harder form of aluminum and is not so gummy or bur prone. Still, I would try stacking parts (4 would only be one inch).
Just as important especially when dealing with thin
parts, you want a reasonably thick (1/2-3/4 inch) backing plate near the diameter of part root diameter to keep the last part from flexing. If you hear ringing or grinding sound, the fixturing is not stiff enough. Part flexing makes noise and usually produces bad finish.