A paying job came in, went and picked it up late last night. It's 3 blocks of 1-1/2" thick O-1 tool steel, heat treated to 62Rc. They're about 4" square. The job is to grind both surfaces, one needs to be flat within .0002" and a 8 microinch finish (or better.)

The hard part is that that came out of heat treat like squared off footballs! Fat in the middle on both sides. Each a little different, the "best" one is out about .004" on each side, the worst nearly .010". All I could get done today was to rough out both sides on each. I used a Norton seeded gel wheel, a 5SG46-KVS. It cut like butter and didn't load up the wheel, although it did need to be dressed again about the time I finished that operation.

Here's a photo of the first side on one, as I had shimmed around it to try and center the bulge. You can perhaps see two of the steel shims under the corners of the part.


Now the second side with the first .001" taken off, proof that the bulge in the middle was fairly well centered and I wouldn't have to take any more than the minimum necessary to get them clean.


I hope to get the finish wheel work done on the parts tomorrow and deliver them, hot job. While I was doing most of this, Neil had come over and made some more of his motorcycle project parts. Only when we have both been taxing the machines pretty heavy did the 60 amp circuit breaker give out. It was a case of me with the 2HP surface grinder, it's dust collector and coolant pump going, and Neil on the lathe starting up at it's max 1800 rpm speed with the 10" 3-jaw chuck that did it. Better that then the main breaker which was constantly giving up on me last year until I replaced it. Been a couple of years of heavy use, I may have to renew the 60 amp one.