Router guides for woodwork are most commonly designated as fixed base and plunge base. The fixed base units can do much the same work as the plunge base machine but are more tedious in adjusting the depth of cut for each successive pass than the plunge type. The plunge base router guide is best suited for repetitive cuts at varying depths. This router guide is equipped with several depths stops usually in a turret arrangement. Each depth stop is set to give a deeper cut than the previous one. The first stop is set for the initial cut. The turret is then turned to the next stop to give a slightly deeper cut while the last stop will give the final depth of cut. Once you have the stops adjusted correctly you can do cut after cut at precisely the same depth without having to use a ruler or depth gauge for each pass.
The first thing that comes to mind about the router guide is decorative edging. There are any number of attractive bit profiles that can add that quality touch to your projects such as Roman ogee, bullnose, and beading, to mention just a few.
Edge decorating is just one of many tasks the router guide can be used for. With the right accessories, you can do inlay work, cut dovetails, make stile and rail raised panel cabinet doors and do lettering for signs.
Some jobs can be done with the router guided by hand but for many applications, a router table is essential for safety and ease of use.