Inserting the Truss Rod
I was dreading the next step - insertion of the truss rod - and my dread was justified. My plan was to rout a straight 1/4" channel down the center of the neck on the fingerboard side. It worked great on a test piece of pine! Then when I routed the mahogany, the router wandered a bit; very depressing. Here is the channel with the truss rod showing. The truss rod is a piece of zinc-plated steel rod with 10-32 threads, about a buck at the generic home improvement warehouse.
Looks good here. Pride prevents me from showing the mistakes. Also shown above is a 1/4" oak insert which will be contoured to make a curved truss rod channel. Here is the nut end. I drilled through to the channel using a hand-held power drill with a long 1/4" drill bit. Success on both ends where the drill bit landed right in the channel!
Here is the oak fitting snuggly in the channel. I think will be OK since it fits well along most of the channel.
Here is the other end of the neck. I drilled a 1/2" hole, then a 3/8" hole. To keep the truss rod from turning, I tightened two 10-32 nuts against each other, then tapped the assembly into the 3/8" hole. Should do. Hey, how often do you adjust the truss rod anyway?