Bridge slotting jig

I built this simple plywood jig for routing the saddle slot to the bridge. "Cam clamps" hold the piece down firmly against the pocket and provide level surface for the router rail.

This mechanism provides well enough force to keep everything in place

I wanted to use my proper router, for my Dremel doesn't give a clean enough cut. With 3mm straight bit,  the router base needs to fit snuggly in between the side bars, and the end stops define the slot length. Mine is set to 74mm. The rail system is simply clamped down to the base, at exactly right place and angle, of course.

I mark the centerline of the slot to the bridge plank to help the rail placement.

I cut in multiple passes, thus preventing the router from tilting when starting the cut.

A clean cut. The depth of the slot is approximately 1/2 to 3/4 of the saddle height, depending on the latter.

My saddle blanks are a bit oversized for a 3mm slot. A little sanding ensures a tight fit.

Here is the target. The original ebony bridge of this pre-war gem was beautiful, but had too many issues (split in half for instance) to be repaired. The replacement pyramid bridge is still rough, waiting for the time to get in shape.