Cutting tools are just that. The tool has to be harder than the material you are cutting. If you are uncomfortable, or unfamiliar with their usage. By all means.' do not try this at home'. Have used pattern bits,(mid-level ), NOT Harbor Freight stuff),to chase 100's, if not 1000's of lin. ft. of 6061, 7075 and 7005 aluminum from 1/4 to 3/4"thick. First trimming on the band saw like you would a body w/template. The Fraued brand bits last quite a while. Have tried Amana and CMT and they don't last any longer but cost more. Also wear safety gear! Using a belt sander will not yield an accurate or straight cut. IMO, the fretboard should be dead straight and not "tapered into the body" It also looks like the string spread could have been wider at the bridge to line up over the pole pieces?