Hello, All, I made a couple of aluminum knobs yesterday, and wanted to put the coarsest, straight knurls I could on them. My problem is that, when done, instead of pretty, smooth knurls, the material surface itself looks pitted and chipped, as you can see in the photo below. I have made several nice aluminum knurls in the past, but used the finer wheels and those were cross-hatched, not straight. I was knurling aluminum, using the coarsest, straight knurling wheels I have (14 lines per inch). I have a "pinch-type" knurler from LMS; see below. I cut the outer diameter of the part to 0.978 inches, which makes the circumference in inches evenly divisible by 14, so that the knurl lines should line up after a full revolution. I started with a very light pass and with the wheels about 50% engaged, and moved slowly across the part by hand. I used old-school, dark cutting oil (mineral oil) as the lubricant and oiled the crap out of the surface and the tool during the process. I wiped the part after each pass and used a chip brush, but it wasn’t too effective at removing all the aluminum particles. You could see that the oil was basically a mix of thousands of small aluminum particles and the dark oil. In fact, after each pass, the lubricant was more silver than dark, in spite of my adding oil as we went. After each pass, I would tighten the knurling wheel some more and reverse direction. I was using a Real Bull 7x14 mini-lathe from Big Dog Metals. I suspect the issue is that there was too much aluminum powder from the knurling process in the lubricant, and it essentially ground the knurls, but I don't know what to do about that as I was already oiling it very heavily. Any suggestions would be appreciated.