Since I had a few extra RAS's around and I had always wanted a radial arm router, RAR, I went about building one. I wanter to use a factory stock router, in this case a Porter Cable 690 series (actually purchased on sale/clearance NEW, $60.79. plus a $10 3 year Sears warranty.) I also wanted to use the RAS carriage without modification, IF this idea didn't work. So, those were the rules.
I removed the motor and wiring and measured the carriage for side plates based on the height of the PC router and the width. The tilt mechanism and handle are all tied together, so the left side plate needed a center hole and 4 mounting holes. The right plate only needed a pivot hole, but also a shim to keep it parallel.
I had a billet of aluminum 5" in dia and 2 3/8" thick which I used to secure the router motor. Only problem I had was drilling/boring sawing a 3 1/4" hole out of the center on the lathe. IT TOOK FOREVER! Then on the final pass with the boring bar I took too much off. DANG!
It all worked out eventually, since I need to bandsaw a slot to allow for compressing it to tighten on the router. A few other slots allowed for the small pins on the motor to slide into.
A 1/4" base plate was all I needed with drilled holes and a hole saw center hole for motor cooling. I drilled and tapped the side plates for the bottom plate bolts. After everything was drilled, tapped and bolted I tested it out and ....