Pie are round but square is best for the base plate for your router
7" or 8" square ....
You can make one very easy and quick,cut some stock in a square, draw a line from corner,,drill a 1/16" hole in the dead center...if you want it round now is the time to make it round using the 1/16" center hole..
Now chuck up your forstner bit ( you need two of them) 1 3/16" and a 1 3/8" ) drill out the bigger hole (but only 1/8" deep) now chuck up you 1 3/16" bit and dril the hole out
Now your guides with just pop in the new plate,,make one more at the same time but this time dril out a 2 1/2" hole for the bigger bits...
To center the new plate for your guides, pop in one of the guides, that has a 1/4" hole in the center, now chuck up a 1/4" drill bit backwards in the router or a router bit, now center up the plate and put the screws in place..
I have one of those combo kits based on the laminate trimmer with a variety of other attachments.
The current month (October, 2009) of Fine Woodworking shows a laminate trimmer with a guide bushing base. If I have what I figure is a standard four screw base, can one of these either be gotten or shop made?
I started to do this with some plexiglass remnants but I stopped because the
trimmer's laminate attachment doesn't look like it has much bit adjustment.