I'm just getting into woodworking. This has been a consistent source of confusion. It's no simpler with rough lumber. The usable yield of 4/4 (i.e. four quarter

I'm just getting into woodworking. This has been a consistent source of confusion. It's no simpler with rough lumber. The usable yield of 4/4 (i.e. four quarter, or a one inch thick rough piece) is at least 13/16 of an inch after surfacing two sides.