Headstock repairs are nothing new in these parts. If you pop by the Haze blog from time to time, you'll probably have seen more than a couple over the last few years. We've also talked about the need to reinforce some broken headstocks with a 'backstrap' (a piece of wood that overlays the repair to add strength).
I like backstraps. They're an effective and discreet way to strengthen a neck repair. They can take a bit of time and effort to do properly, though, and splines are not the only game in town. There are times when an alternative is preferred.
Splines are the prime candidates.
Spline Headstock Reinforcement
A spline is a slat of wood that's inlaid into a channel cut in the neck.
The idea is that the channel runs for a distance either side of the repaired crack. A slot is routed and the spline glued in. The newly inserted 'good' wood of the spline ties together the good wood on both sides of the crack.
As you might expect, the splines are carved down to match the neck and the finish touched up. Splines are not quite so inconspicuous as a well-executed overlay but they are an excellent way to bolster a neck repair that needs some reinforcement.
And, in the right circumstances, you can even get inventive in your splines.