Routing truss rod channel in bolt-on extension

[Cutty]

After struggling with understanding how 'the book' does it using a table router, and much head scratching, I repurposed the (failed) first version of the bobo mortise jig I made and mounted the router to it.

The pins in the jig locate it central in the existing slot in the neck to slide it along. I was even able to use it to extend the slot towards the head as I hadn't cut it long enough originally.

[Mark McLean]

Thanks Cutty. That looks like a robust and reliable jig. Can you show how the router base fits into the cutout slot? What is it that registers on the insides of the cutout?

[Cutty]

G'day Mark,

There are three aluminium pins on the base of the jig that are originally used to locate it centre on the existing truss rod channel when routing out the pocket for the bolt on neck extension.

In this iteration, those pins still sit inside the channel and stops any lateral movement, but the base can slide along the neck (i.e. left and right in the first picture).

The router base is screwed onto the platform on the opposite side from the pins so it is fixed in position. I did consider just drilling a hole in the centre line of the platform to put the router through but that wouldn't have fitted into the existing groove.

Not sure if the picture below explains it any better...

[kiwigeo]

After struggling with understanding how 'the book' does it using a table router, and much head scratching, I repurposed the (failed) first version of the bobo mortise jig I made and mounted the router to it.

On a table router I use a 1/4" spiral up cut bit. The neck blank is set up so one side is the reference side which runs against the router table fence. Your method will work as long as you're not doing the Gore classical neck where the truss rod channel varies in depth to acommodate the fretboard "wedge".

[Mark McLean]

Ahhh, I get it now. The whole jig slides along the truss nod slot, and the router is screwed down to the wood plate. Nice.