There are several ways to build saw horses. They are either built to satisfy an individual own requirements. Height and width to serve its intended use. ou can also buy folding ones or kits that allow you to assemble them by just adding 2x4's. One ofthe simplest methods i have seen is where you build an "H" shaped structure from 3 pieces of 2x4's (this component will be used for thecross bar). Then simply cut 4 legs the length you would like. Attach the legs to the H such that the top of the leg sits just under one side of the H ( assuming that you have turned the H on the side). the second side will force the legs to be spread to a good angle.