I was brought a Fender Japan 70s reissue Telecaster with a broken truss rod for repair. The threaded part truss rod had broken at the headstock.
I extracted the truss rod from the heel of the guitar and found that there was still over 1cm of thread left on the end. My solution therefore was simply to move the truss rod forward in the heel by 1cm, and hold in place with a maple fillet.
Once the neck was refitted there was no sign of the repair as it is all hidden in the neck pocket and as no parts were required, it was an inexpensive repair for my customer!