super simple! Twist a nut, set depth, twist nut. Using a router plane makes detail cleanup a cinch. Check out some commercial ones and their prices and then look at your cutoffs and old messed up steel items. Make one? ofcourse you can! Here are some helps in the process. Lots of cats to skin in this project.
http://wwwcdn.popularwoodworking.com/wp ... rPlane.pdfhttp://www.inthewoodshop.com/ShopMadeTo ... Plane.htmlAnd a video.
http://www.monkwerks.org/tool_build/router_planeThe really cool thing about the concept is that you can shape the cutter to do many tasks, diamond, skew l or r or even toothed as well as changing sizes from super narrow to really wide. Allen wrenches are usually so cheap as to be expendable and a set can yield a bunch of cutters if that is what you use to make your cutter.