Trussed up

It was time for more work on the neck. The main job that needs doing structurally is inserting the truss rod. I'll be using a double action truss rod which just needs a straight 6mm rout down the centre of the neck. 

My usual method is to run the router along the edge of the neck blank, using a fence to keep it centred. However, I forgot to plane a straight edge along the side of the neck blank. Now that I'd glued on the heel, and given I don't have a decent vice in my shed yet, this would be slightly annoying to do now. 

Instead, I straightened an edge by running a follower bit along a straight piece of mdf, changing the edge of the neck blank from this:

To this:

Doing it this way at least meant that the edge of the neck blank was guaranteed to be at 90 degrees to the face - using the router made sure of that. However, it took was longer than the five minute job it would have been with the plane had I not already glued on the heel extension :)

Next up I spent a long time measuring up the neck, body and fretboard. The neck will join the body at the 16th fret, which, using the pre-slotted fretboard, means we can mark the position of the nut on the neck blank. From here, we can add the width of a 5mm thick nut and the positions of the fretboard and truss rod then cascade:

I marked the start and stop position of the truss rod and set up the router fence and depth stops:

I then made passes along the neck blank, increasing the depth of the router bit as I crept up on the final depth: 

...until...

With the body end of the truss rod sorted, I looked at the nut end. the truss rod adjuster is about 8mm thick, so needs a bigger rout to locate in the neck:

I routed this in, stopping before I came to the nut's location. I wanted there to be a 'bridge' of wood across the truss rod for the nut to sit on - the internet insists this makes a tonal difference (*coughs*). I was hoping that I could drill this out:

And, using increasing sized drill bits, I crept up to the required size:

I suspect that this was a bit of a hacky way to do this, but I was very happy with the result, but the next (and final) drill bit I used to get the access hole to its correct size caused the bridge to break - it just got too thin. This was annoying but not the end of the world - it will just mean that the truss rod will be visible once the nut is out:

After chiselling out a fraction of a mm from the bottom of the truss rod channel. The rod fits in perfectly along the length of the neck:

The last thing to do was to glue on the headstock. I drilled a couple of locating holes to stop it slipping around on the glue and securely clamped it on: 

I'll leave it overnight to cure fully. 

The neck blank is now in one piece. The next stage will be to shape it. My method of using a drill to create the truss rod access hole was that of a cowboy, and I probably removed a mm or so of wood more than I should have. I don't want to weaken that part of the neck, so may create a volute at the joint. 

It's obviously off spec, but I like the look:

 I'll have a think.

More neck blank preparation

There was a little more work to do on the scarf joint. It needed a little more sanding in the jig to get it completely smooth:

And finished, note the little block to support the edge of the slope face - it's very thin and would snap off easily:

The edge of the slope will be where the nut sits. It's key that this is at 90 degrees to the centreline of the neck. I checked this with the set square, and it was fine:

Out of the sanding jig and with the scarf joint set up, this is the side view of the neck against its template:

The headstock angle matches the template (although the wood is too thick currently):

But the mahogany is too thin at the heel end.

The heel will be built up by gluing another block of mahogany onto that part of the neck blank like so:

I spent a while sanding and checking the surfaces that would meet to ensure they were completely flat and that there would be no gaps through the whole joint. After this the joint was clamped, glued and left overnight:

The neck blank is nearly done, however, it is too thick. The next steps will be to mill it down to closer to its final thickness using the router.