Above: If you have a Craftsman router and would like to buy an adjustable guide - here's one for $20.

After making another trip to another hardware store, this time Sears, we picked up a router guide that would supposedly do the trick for about $20. After returning to our workshop and examining it a bit more closely, we found that the screw mounting holes did not match up at all with his Black & Decker router. Dangit! Should we drill new holes into the plastic guide... or should we just go ahead and make our own? In the enduring spirit of DIY, we decided to construct our own. All we needed was a guide to assist us in creating circles of three different radii.

Above: You could buy a circle jig that's designed for your router... or make one yourself in less time than it takes to drive to Sears.

Above: Our pilot holes were drilled with dead-on precision.... mostly.

Throwing together a simple circle guide is incredibly easy. Just rustle up a thin piece of scrap you probably have lying around the shop somewhere. Then cut it into some managable shape using a jig or band saw. Measure and drill the holes you'll need to mount the device to the bottom of your router and also a large hole that will allow your bits to poke through. Finally, drill the appropriate holes that will act as a center point for your circles. (This of course is the radius.) Be sure to measure from the outside of your cutting bit to the center of the fulcrum holes!

When you are ready to cut the circles for each radius, just push a nail through your center guides in your handmade jig. Be sure it fits snugly. Before you go ahead and spin up the router, be sure to drill a hole for the fulcrum into the MDF of equal size to the nail to eliminate wobble. Also drill holes that are large enough for the bit to fit into at the edge of each circle.