You could also bore a hole in a piece of MDF to fit a bushing plate to hold the router in place and the drill a pivot point (or several in the opposite end.
I occasionally need to make acrylic or polycarbonate diameters, the last one was 52". Needless to say, boring a center hole is not an option. I use a vacuum cup and pump to center a jig to which I attach my MFS and use an 1/8" plastic cutting bit in my 1400...small bit to reduce torquing.
I use a piece of mdf with a 30 or 40 mm hole on one end and a 5 mm hole at the radii. Peter Parfet has a video on the process. This method allows you to use any router without tangling up hoses and cords.
Like Darcy, a board with a hole. Sometimes I screw the board to the router base, or I use a bushing that fits the hole. I have a bunch of the boards, each one marked for their particular project.
Thanks [member=11196]Peter Parfitt[/member] I ended up ordering the MFS400, but this looks like a great method for doing the larger circles I will eventually have to create.
Peter Parfitt said:
Hi Edward
I made a video a long time ago about a trammel. I have recently used it to cut a circle about 860 mm in diameter. Here is the link: