rockler dovetail jig

Reds, it's not you... its your router. Craftsmen routers come in many flavors and types. From what I know about my own Craftsman my guess is you will find an opening with 3 screw holes around it in your base plate. This base plate is designed to work with Craftsman guide bushings only. I know my 2 guide bushings are plastic and flimsy to boot. The good news is this is a simple fix. You can buy a replacement base plate for your router that will accept the Porter Cable style bushing that came with your jig. Many aftermarket companies sell base plates. As long as you need to change the base plate anyways, consider the options. Clear is nice, gives you a bit more view of your work. Oversize is very handy for use with jigs and fixtures. Some have circle cutting features built in. That said, you can build your own out of 1/4" Masonite or plastic. Round or square is fine. Remove your base plate and use it as a pattern for the 3 mounting holes. Buy yourself a 1/8" veining bit, these are very cheap, (maybe $2) and mount it in your router. Attach your base plate and slowly plunge your bit through it for a right on the money center point. Remove the plate and off to the drill press where you will drill 2 different sized holes to mount the collar. Forstner bits are the answer for this job. The bottom hole is first. Its larger and goes only deep enough to give you a small lip. Then drill down from the top side with a bit the same size as your threaded sleeve. If you measured right your guide bushing should mount up perfect now. If it sits below the bottom surface you can easily reinstall the larger bit and adjust the depth to flush. This 3 step drilling process may seem silly at first, but it allows you to use the 1/8" center hole to locate both drill bits.
Hope this helped.

Craftsman is pretty much proprietary stuff. It is designed to be different than what other people sell to keep the business at home. The short answer is you will need to buy PC style bushings. Brass is preferred over steel bushings since there is less chance of it nicking a bit during set ups plus the brass bushings don't tend to loosen up like the steel ones do. The good news is many companies make/sell them so you are more likely to find a good price. I found my set on sale at Rockler for $19.95 last year. Keep your origonal base plate and guide bushings together. I bought a Craftsman commercial router for $20 because it didnt have a base plate. Get the idea?
I will post a photo tomorrow showing my Craftsman with a guide bushing installed. I will include photo's of a PC style base plate, a Bosch base plate and the 4 different types of guide bushings I have. You asked an excellent question, it comes up for just about every brand out there. The photo's I post should help many users.