03-17-2014, 08:56 AM
Hey Ed, all in fun. 
You're right - I should've posted a pic right off. That's a "finish pass" of .0002 with a 38A47K wheel. The catalog says that's too shallow for that grit, but I thought I'd try it anyway. Catalog says for under .004 use a 60K, .100 cross over. That didn't work either; it just made wider burn marks.
I bet those *are* aluminum strips (going north and south in the pic) and they're being embedded with dark debris from the wheel. It just dawned on me that the aluminum might be loading the wheel. I'm dressing the wheel gently at about .002 and then a quick pass over the nib at .0005" as fast as I can crank the wheel. It's a manual, rack & pinion.
For some reason I had better results going harder, from a 60H to a 60K, meaning I could make it about halfway across before burning, but 3"x12" of it looked good. Definitely loading and/or dulling, a dark streak forms on the wheel. Looks like I need to get a couple more wheels and experiment.
You're right - I should've posted a pic right off. That's a "finish pass" of .0002 with a 38A47K wheel. The catalog says that's too shallow for that grit, but I thought I'd try it anyway. Catalog says for under .004 use a 60K, .100 cross over. That didn't work either; it just made wider burn marks.I bet those *are* aluminum strips (going north and south in the pic) and they're being embedded with dark debris from the wheel. It just dawned on me that the aluminum might be loading the wheel. I'm dressing the wheel gently at about .002 and then a quick pass over the nib at .0005" as fast as I can crank the wheel. It's a manual, rack & pinion.
For some reason I had better results going harder, from a 60H to a 60K, meaning I could make it about halfway across before burning, but 3"x12" of it looked good. Definitely loading and/or dulling, a dark streak forms on the wheel. Looks like I need to get a couple more wheels and experiment.