A thread to post your clever jigs that failed.
I was trying to make some small corner shelves this weekend, and spent most of the morning building this not-so-brilliant jig for my router table. The idea was to build a pivot that could be moved relative to the router bit, so as to give me an adjustable radius for use in different projects.
But what I didn't think through was that the pivot is not right at the corner of the workpiece, so the radius would not be constant. Starting the cut at the corner was fine, but as the piece turned, the cut gets deeper and deeper until you hit the mid point. Even if I was OK with a non-constant radius, the problem ended up being that as you cut the hand pressure needed to hold the piece in the jig got really high, and it ended up kicking the pice across the shop. (No injuries, I wear a face mask and keep my hands clear). It could still be used, if you started with very light cuts at the center, and worked your way out over many passes. But you end up with an ellipse, not a circle.
I ended up mounting the router on an arm, and making a pattern from OSB, and then using a pattern-maker's bit to do the curves (the photo is from afterward).