Inspired by the excellent video I posted about yesterday, and constrained by the weather (it is raining and my “work area” is outside) I set about planning out how I’m going to do the top carve. On a Les Paul there are two different parts to the carve: The first is the traditional archtop shape we all know and love, the second was something of a revelation to me – the top is carved flat, rising from where the neck join starts to where the finger board finishes. This means that despite having an angled neck, the fretboard still runs parallel to that part of the body.
Whilst it is not a Les Paul, this picture from the MyLesPaul forum really clearly shows the two different parts of the carve.
So tackling these two carves separately, first off I taped some translucent paper over the body, marked up the centre-line, and for the top half of the guitar roughed out the two main steps for the carve (highest and lowest) freehand with a pencil.
I folded the paper along the centre-line and then replicated the shapes for the bottom half of the body.
I bisected the two lines to draw the third step, again, freehand. The maple top is 19mm thick and I want to leave the edge at 5mm, so for the low step I’ve got to rout away 14mm. The top step is going to be a depth of 2mm. The centre step therefore will be 8mm. I may yet decide to add two further steps at 5mm and 11mm depth, just to minimise the amount of sanding I’ll need to do. This diagram gives you a rough outline of what I have in mind (not to scale).
The next step will be to turn my paper template into router templates, using 6mm MDF sheet. I’ll start by cutting the paper to lowest step, transferring that to the MDF, cut the paper to the next step, transfer to the MDF… and repeat all the way up to the top step. This will leave me with up to five templates.
One of the things that concerns me is that, while cutting around these templates, it is very easy for the router to tip away from the vertical, and cut too deep, and at an angle. To guard against this I’m going to build a box to fit around the guitar body, and a large footplate to ride on top of this box. This will guarantee (I hope) that the router always remains vertical.
An added benefit will be that hinging the box at the front side, and shimming up the back will allow me to cut the neck pocket and the flat front-to-back carve at exactly the right angle. I was inspired to this approach by reading this “Luthier Than Thou” article about carving Les Paul tops and neck pockets. I’m going to adapt the same basic principle to kill two birds with one… er… wooden box.
Update: I’ve since found a picture of exactly what I had in mind on the MyLesPaul forum.