Truss rod broke through the rear of neck.

[Mike Perez]

My first guitar I built in 1982. Rickenbacker 320 style. All hand tools.
As it was drying, hanging from the rafters, the rope was caught and when I shook it loose, it slipped and bounced off of the hook at the end of the rope. It landed on its tail end, bounced and landed again on the fingerboard face.
The fingerboard came loose at the fist three frets so I glued it up and when I used clamps, I over-tightened one and caused the read of the neck to give way over the truss rod and it broke though.
It's been this way for 40 years. Now I want to fix it.
My plan is to route/chisel away some of the neck on both sides of the truss rod at the first three frets, cut a piece of maple, slot it to go over the truss rod, gluing it to the neck. I'll need to take away some wood to give the piece some new surface, so I'll widen the new glue area. It will end up having a hump to beef up that part of the rear of the neck.
Anyone have this repair before?
Thank you for any help,
Mike

[Barry Daniels]

Never done that one before. Can you post a photo of the problem area?

[Mike Perez]

Hello.
I just got back to working on this guitar.
Lots and lots of distractions (and a horrible case of the shingles), but I'm back ready to get to work.
The black dot is the area that the truss rod breaks through if there is any pressure on the rod.
The wood is less than 1/16" thick there.
What happened was, when I was painting the guitar, it fell from the support.
The fingerboard separated at the first fret so I re-glued it.
In the re-glue, I put too much clamping pressure, and caved in the rear of the neck.
I played it like that for 42 years!
Now, I decided to finally fix it.
And my wife says I procrastinate? Ha!

Thank you,
Mike

[Michael Lewis]

Just poking my old nose in here. This situation is a bit unusual but not unheard of, and needs some material added. This is a prime example of where a "back strap" will be used. The procedure is to remove some material from the whole back surface of the head stock down into the shaft of the neck and replace it with a 'plate' of new material that covers the head stock and well into the back of the neck for a couple inches or more. You need to heat and bend the new material to conform to the newly opened surface where it blends into the shaft of the neck and covers the truss rod slot. I think there should be some information about this process in the LIBRARY (I have not checked lately). This process is most often used to repair a broken off headstock, but this situation is just as worthy.
The concept is the new material will be able to withstand the tensile stress when the strings are tuned to tension and it covers up the truss rod slot. So use structurally sound new material for the "patch". It is on the back of the headstock so figure is of little importance, and straight grain material will be stronger and likely less problematic for bending to conform to the new surface. Make it fit well and let it dry thoroughly before trying to glue the new patch into place. Once it is glued and dried then shape it nicely and then do the finish touch up/repair. Do some thinking about the process BEFORE you get the glue : clamps, cauls, whatever you might need to hold the pieces in place while the glue dries. Do a trial clamping BEFORE any glue is applied just so you can make sure everything fits and aligns properly. Then be aware that when you add the glue that it can be slippery! So watch out for that. If it slips away from you just take it back apart and clean off the glue before making another attempt. This is not rocket science but it still can be a bit tricky. Take slow deep breaths and relax. You can do this.