A two-man project while Mayhem was visiting me. He had asked for some pointers on using a surface grinder as he has one now. I suggested we make a low but big V-block to help setup angle milling tool blocks for the quick change tool post he's got on his newer lathe. Sketched it up, cut up a piece of 2" x 4" x 5" 1018 CRS to 4" long and went at it. Of course 4140 pre heat treated would have been my choice, but this is all I had and it'll work fine.
Start by setting it in my vise at 45º and hogging it away. Yeah, could have perhaps sawn it out rough but milling it away took under an hour with a Walter F4041 shoulder mill. About 650rpm (425 sfm) and fed by hand, 0.100 depth per pass. Lost almost half it's weight.
Lightening it up a bit more, 4 holes of 15.3mm though removed nearly 11 ounces. Two down, two to go.
First ground the long side clean and square, then a creative way to hold square and parallel for establishing the large flat surface square to the sides.
Clamp to a good angle iron I have, grind the top surface flat, then flip it over and grind parallel. Using my Starrett bevel protractor to set the 45º angle exact, clamp to the angle iron and grind flat the surface we'd milled for the Vee. Dressing a relief into the face of the wheel, we face ground the adjacent surface in the same setup. With one minor setback resolved, we got it done.
And the final result, every flat surface on it ground square, flat and parallel. It came out GREAT! We're both very happy we did it.
You can just make out the nice cross-hatch pattern from face grinding.