I made a picture frame spline jig for a frame I am making for a certificate. It’s for my brothers Masonic cert. it made from birch ply and a 2×4 spruce. It fits around my fence with sacrificial plywood and slides very nice. To make the cut or cuts I clamp the frame to the jig with a 5" C clamp. I put a dowel on top to act as a handle well away from the blades path.
-- CHRIS, Charlottetown PEI Canada. Anytime you can repurpose, reuse, or recycle, everyone wins!