I recently built a router table for my new ridgit router. The only problem I seem to be having is getting the bit centered on the brass bushing. I used the clear plastic piece off the bottom of my plunger and routed a hole for it to fit flush into the table. I then screwed 1" screws through the table and base plate into the router. When I adjust the depth of my router and tighten the base back up it throws the bit off center. It isn't much but I really want to make some tight fitting dovetails. Any suggestions?