Honing w diamond paste

[Bruce Haugen]

I worked in a plant that tore down a huge engine (3,500 hp diesel). I got one of the port covers. I’d suggest a scrap yard. Or you can look for something called dura-bar or grey cast iron. A local community college with a machinist program surface ground my plate for free, as practice for their students. I also have a chunk of a cast iron bathtub that works just as well.

I know of people who use mild steel, too.