This tool is inspired by Ted Woodford’s design seen in his YouTube video “Rearranging a 1934 Martin”. I recently found myself staring down a Martin 0-18T side crack that was mis-aligned. I could push the crack into alignment with my fingers inside and outside the guitar, or I could glue the crack, but I wasn’t going to be able to do both at the same time! I’ve never been a fan of the cobbled together turnbuckle tool I made years ago. It never seems to be the right length, and it’s hard to set up inside the guitar. Ted’s design addresses both of these problems.

I made the Prop ends small and with a radius because of the way I needed to use it in the 0-18T. I imagine there will be situations where I want a different radius, no radius, or larger ends so I made the Prop end file parametric and the dimensions can be modified to suit. I appreciate that 5/16-18 threaded rod is not available everywhere, so I’m providing the parametric file for the Prop end that uses 8mm threaded rod. The Prop bushing should fit both sizes of threaded rod, but I’m also providing a parametric file for it in case the inner diameter of whatever 1/2 PVC pipe is available has a different inside diameter from what I found.

The 30mm knob is a publicly available design, and I found if I scale xyz in the slicer 106%, it works for a 5/16-18 nut, and if xyz are scaled to 109% it works for a 8mm x 1.25 nut.

The length of the 1/2″ PVC tube and threaded rod should be cut to suit. The PVC tube in the one pictured is 9″ and works across the body, but I’ll probably build another one that has a longer tube for cracks that are near the strap button at the bottom of the guitar.