Workshop: Those Evil Dowel Joints

You know how I'm always talking about "doweled" neck joints on old Regal and Harmony instruments and how I need to reinforce them somehow?

This is what I mean. They use either a big (in this case) or small (in many cases) dowel at the top of the heel and cross their fingers that it won't fall apart. I guess it works for a while, anyway. The only sure way of reinforcing these is to add a bolt or screw under the dowel, from my experience.

I've tried additional dowels (works fine for ukes) but the tension on the joint is too high for something like this -- a 1920s, nice-grade Washburn-branded Regal-made 2-point mandolin. When this is done there will be a screw installed, the neck will have extra back-angle to correct compression over time, and there will be a pearl dot hiding a screw-reinforcement in the back of the heel.

Note that I've removed the fretboard extension -- it had warped "up" over time and needed reshaping, anyhow. Also, to easily remove the joint, one needs to twist on the dowel to loosen it up (something that doesn't work with the fretboard attached).