It helps to have something I call a knife parrallel. This is a parrallel that has one end with a wide base that is placed against a vise jaw, and the thin end (not really a knife edge) goes against the stock.
First step is to machine the top face flat. Once flat, this face goes to the rear and mates to the rear jaw of the vise. The knife parrallel is used as a go between the part and the moveable jaw of the vise.
Machine the exposed width. You now have the original top and a side square to each other. Flop the part so the original top is to the bottom and the machined edge is to the back. Use the knife parrallel so that the moveable jaw isn't changing the way the block sits when clamped. Some small parrallels betwen the visde and stock will let you tap the block with a l;ead hammer or dead blow until both front and rear parrallels are tight.
Now machine what was the bottom in your first cut.
Flip the stock so the machined edge from the second step is now on the bottom. Both mai9n faces are to the front and the back and the knife parrallel is no longer needed. Tap the block down onto parrallels once more so they are tight and machine the exposed edge.
With both faces and twoedges done, it is a simple matter to use a long enough endmill to machine the sides of the block hanging out from the edge of the vice.
The main thing is that the vise is trammed and square to the table, and the head is trammed and square also. If the head isn't trammed or the vice isn't square, the best you can do is still garbage.  |