Be A Copycat For Perfect Hole Alignment
The tough part of attaching shop-made jigs and fixtures to a router is drilling the mounting holes to match up with the holes in the router base. I found an easy way to make a pattern of the router-base hole layout: Copy the router base on a photocopy machine.
After making the copy, check it against the tool base to make sure it's exactly the same size. (Some copiers are off by a few percent, so you may need to adjust the copier enlargement or reduction factor.) Once I have the pattern, I tape it or trace it onto my jig and drill the holes in the right places the first time. I sometimes need to reverse the pattern or make a mirror-image copy, depending on the way I plan to use the pattern.
I also make patterns using my computer's scanner. After scanning the base plate, I can flip the pattern with my drawing software if I need to. I can use the same software to mark exact centers in the holes. I stored the pattern file so I can print one out whenever I need it
—Matt Besser, Urbandale, Iowa