When ripping wood we want the blade high enough to have as few teeth as possible touching the wood to reduce friction and burning. When cross cutting we want the blade much lower. Some say it should be 3/4" above the wood, I say just getting three teeth above the wood. In either case the idea is to come out of the bottom of the wood at as low an angle as possible to minimize splintering on the bottom. Burning is rarely a problem on cross cutting.
Learning Curve 115