Acoustic Guitar Build

Preparing the Top, Back and Sides

I got the back plates out and trimmed off a few mm from each of them to get rid of the worm holes and get the figure properly symmetrical


I trued the edges using my (now nice) plane.


It took me a while to get the joint line perfectly tight, but it made all the time spent tuning up the plane worthwhile when I eventually got the plates to meet without even a hint of light between them when held against a window pane.

There’s still quit a bit of light showing here, but the joint perfectly tight when I’d finished


I thought that I had better glue them while the surfaces were fresh – I clamped some blocks against the edges while the joint was raised on a batten, then pressed them flat to apply pressure which seemed to work very well.


Flushed with success, I jointed and glued the top plates, too.


This is them after a quick going over with a scraper, with my revised outline tentatively marked on them (if you can make it out) – I favour the higher placement of the two marked on the top as it makes the grain at the outside of the bouts more parallel to the guitar and avoids cutting the darker grain lines quite so abruptly.


I cut the top and back roughly to size with my little bandsaw and got the  sides roughed out, following the template in the plan, but allowing an extra 3mm, top and back, for trimming to final shape:


I planed them down to 2.2mm per the plan. (I used a dial gauge mounted on the gantry of my CNC router to measure the thickness at various points).

The numbers on the sides is their deviation from target in 0.01mm. I think they’re reasonably uniform (worst is one side that has an edge that is 0.1mm under – nothing is significantly over thickness):


^Note safety sandal 😉


The plans give 2.5mm as the back thickness, but some areas were below this already. I evened everything out at about 2.4mm, which (from what I can gather) is still a sensible thickness for a rosewood back.


 I’m glad that the wood came already thickness sanded and I only had to remove a few tenths of a mm. The rosewood certainly takes the edge off a plane iron quickly!