The belly cut, heel transition, and forearm contour all help finalize the shape of a guitar or bass body. They can really change the shape and look of the body. I’ve used a lot of different tools and methods to do these final carvings. In the past, I have used coarse rasps, gouges, shinto rasps, sanding drums attached to a drill, and scrapers.
This time I tried a new (to me) method. I have seen a few other luthiers use angle grinders and while they look aggressive, they look very effective.
I would not necessarily recommend everyone take an angle grinder to their guitar, but if you are comfortable with power tools and want to give it a try, I say go for it. It was a lot of fun and it really cut down carve time for me. You might just want to try it on scrap wood first.
In a short time, the angle grinder (followed up with 120 grit on a random orbital sander) converted my bass from this:
to this:
It’s subtle, but a big difference at the same time. The final shaping really highlights all of the layers that were hiding in the body and was a pleasant reminder of why I took the time to make all of those layers. It takes it from looking pretty good to really great, in my opinion.
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A lot of people have been asking me if the angle grinder is hard to control. I didn’t find it hard to control at all. Like most rotary tools, clamp your work, let the tool start before touching it to the wood, work carefully, keep it moving, and stop and check your work often. Don’t put extra pressure on the tool against the wood. The disc will do all of the work on its own. Of course, you’ll need to wear proper safety equipment as well. I could see this being a pretty dangerous tool if not used properly.
I used a 60 grit flap disc on the angle grinder to do this carving. It worked really well for me. Since this was my first time using it, I haven’t tried any other attachments yet. The flap disc worked so well, I’m not sure I would need to try a different disc for this kind of work.
The initial rough carving of the belly cut took about 2.5 minutes. I went back to it later to finish it up which took maybe another 2 minutes. This will definitely be my go-to tool for carving in the future.
I did the same with the heel transition, which took a little longer because of the shape and the harder woods. Wenge and maple don’t cut as quickly as black limba. You can view that video by hitting the right arrow on the video above.
Here’s another angle of the heel transition.
I then flipped the body over and worked a little carve into the front for a forearm contour.
I couldn’t help but keep going for a little more detail around the beveled edges on the front.
It cuts like butter and took very little clean up with the random orbital sander to get it finalized. That being said, you really need to watch where you start and stop to make sure you don’t start digging in too far. This thing would be able cut through your fancy wood way too quickly if you’re not careful.
A little bit more fine sanding and this bass will be ready for me to apply finish.
