I cut the router plate using the router with a homemade circle jig. The circle jig is real easy to make. Look on youtube for ideas. Mine is made from a piece of scrap Masonite and uses a couple of bolts and wing nuts.
The shelf bracket holders you see were something I had laying around. They are 7' long. They don't need to be anywhere near that long, but I didn't want to cut them in case I decide to use them for their intended purpose. These are old and the metal is heavy. I'm unsure if modern ones are as good. I was really surprised that when oriented with the open side like a C how stiff they are. They don't give at all under the weight of the router and plate. The shelf brackets are only needed for wide work pieces.
I really need to install a removable stop on each edge of the plate to keep the router from sliding off the rails into the work. This can be just about anything: 4 bolts, a block of wood, a piece of L aluminum, etc. I will do that before I use it again.
The pictures show
1) Plate.
2) Rabbet on the top edge of the plate to accommodate the shelf bracket holders.
3) Plate with the bracket holders in place -- I didn't bother to screw them into the sides as this is just show and tell.
4) Rails on the work table. This are about 2" x 2". The exact dimension isn't critical. They need to be true to give you uniform height from the table. These have been outside all winter and now I'll have to figure out how to true them up again. These can be screwed into the work table or clamped, depending on the size of the work piece.
5) and 6) The work piece held by wedges. Once knocked into place, it is a solid hold.
7) The plate over the work piece. Imagine the router on top ;-}
![Cool 8)](./images/smilies/icon_cool.gif)