I've always been curious to integrate CNC technology with my guitar repair work, I started teaching myself CAD design and CNC programming over the past year and immediately started finding ways to use it in my instrument repair work. This can be a big time-saver on what would normally be a very labor intensive job, and it's also very fun to do. There are times, however, where you may be spending more time digitally designing rather than doing the work by hand to begin with. It's important to make that decision very early on during a project.
As a side note, doing these types of jobs by hand is also of course crucial while you're learning and honing your craft. It is a must if you want to be taken seriously as a luthier and shouldn't be sidestepped.
The purpose in this case was to reduce labor time and keep costs down on this nearly abandoned guitar which was badly damaged from the top, and had a broken bridge plate. As soon as I started to take it apart, a large broken section of spruce under the bridge's footprint caved in, pretty much as I expected.
After I cleaned up the damaged area a bit with my dremel tool and straight edge along with a sanding block, giving me some straight lines to work with on top and a slightly "ramped" surface underneath to fit my patch, I then snapped a clear and straight shot with my iPhone and transferred the pic into my computer/CAD design program.
In less than 1 hour and 15 minutes I had digitally traced and designed a 3D patch, made a test cut, adjusted my design with some final tweaks, and bam: I had a final cut of the spruce repair patch from my CNC machine.
After a few short minutes of final sanding by hand to get a tight fit (I had intentionally scaled everything oversized by about 0.015"), I had a perfectly fitting patch to repair the soundboard.
Normally this job would have taken me several hours if done completely by hand, and in this case the customer simply wouldn't have been able to afford it. I then CAD designed a new maple bridge plate and a slightly oversized rosewood bridge, and cut them out on CNC as well.
All in all I saved my customer a few hundred dollars and myself several hours of tedious labor. I'm excited to take this process further in my future repair work whenever possible