Custom CNC Electric Guitar & Case With Mobile BUILT IN Amp!

I am Cooper Nichols, a freshman at Cal Poly - San Luis Obispo.

I've been playing the guitar for a couple of years, and I have always wanted to make one of my own. This digital fabrication challenge seemed like the perfect excuse to do it!. The neck and fretboard were made using the CNC router to achieve precise placement of the frets and truss rod. The semi-hollow body of the guitar was formed using a laminated stack of nine laser-cut layers.

After the guitar was built I needed a good way to get it around. I also wanted to be able to play it anywhere, even in remote areas without power outlets. This case was my solution. The exterior shell is heavy duty in order to stand up to the airport baggage system, and the guitar floats inside of it on laser cut foam cushions. Additionally, the case has two in-built preamps, a tone adjustment board, electronic crossovers, a Bluetooth adapter, and a 200 watt power amp. The woofer and tweeter are built directly into a closed 12.9-liter enclosure, and the whole system will run off of wall power or standard 18v Ryobi batteries.

I designed this guitar to sound and look like a semihollow thinline while maintaining the geometry of my acoustic guitar. I'm new to the electric guitar world and I like a more acoustic sound so this seemed like a good hybrid of my priorities. Maintaining the length of the neck and the fret spacing from my acoustic guitar also makes it easier for me to jump back and forth between the two.

I took measurements off of my acoustic as well as friend's electric guitars and combined them with some calculations about internal volume and f-hole area to create an entirely original geometry.

After completing the design I hopped over to Fusion 360's manufacturing workspace to create the CNC toolpaths for the neck and fretboard.

The fretboard was easy because it only needed to be machined from one side. I used a 3D adaptive clearing toolpath to remove most of the material and came back with a parallel surfacing path to do the final shaping. I finished with a pencil line path to cut the slots for the frets.

The neck needed to be machined from both the top and bottom so it was slightly more complicated. Before I started developing toolpaths for the part I created an operation that cut out a pocket in the spoilboard to help me realign the stock after flipping it over. The CAM for the neck itself looked very similar to that of the fretboard. 3D adaptive clearing paths removed the bulk of the material and then various surfacing paths brought the part to its final shape. It is also worth noting that the WCS is based on the same corner of the stock before and after the part is flipped to eliminate and shift in the Z-axis.

To fabricate the parts I took advantage of a Shopbot Max ATC router that we have at school. The neck is made from yellow maple for its rigidity. The fretboard is made from a remnant of South African rosewood. This stuff makes most hardwoods look soft, so I ended up having to reduce the mill's surface speed and federate slightly. I ran foam test pieces for both parts to avoid messing up the real thing.

As stated in the introduction, the body is a glue-laminated stack of nine laser cut layers. There are four different profiles throughout. I tried this once with the raw profiles shown in the fourth picture, but it was very challenging to keep all of the pieces aligned. I recut them with holes for 1/4" alignment dowels, making the glue-up process much easier.

After the glue dried I trimmed the dowels with an oscillating trimmer and sanded them down flush. I went around the perimeter with a 1/4 inch roundover bit and then clear-coated the whole thing with polyurethane.

I got the electronics from a replacement Stratocaster top plate. For anyone looking to do this project who doesn't need the highest quality pickups this is a great option. Buying the whole set of electronics on the plate is much cheaper than buying them all individually.

I glued the dowels into the fretboard using the same technique as I used on the body. Then I installed the truss rod and glued the fretboard to the neck being careful to keep the edges of the two parts aligned.

I hammered the frets into the slots and then leveled and trimmed all of them with an aluminum bar that I faced on the mill and double-stick taped sandpaper to.

Lastly, I installed the tuning pegs and rubbed some mineral oil into the fretboard.

All that was left to do at this point was bolt the neck to the body, string the guitar... and play!

I decided to make the neck a bolt-on for this guitar so that the pieces could be replaced independently if need be. I have never made a guitar before, so I thought it would be better to hedge my bets against needing to scrap the entire thing. So far it seems like a good instrument, but if I ever decide I want to swap out the neck or the body I will be able to continue using the other part.

After drilling the holes and installing the fasteners, I hooked the guitar up to a friend's amp and put the instrument to use!

As mentioned in the introduction, I wanted this case to be robust and to serve as a self-contained amplifier. To begin, I picked out the audio components that I wanted to use and blocked them out in Fusion. Then, I imported the nominal guitar geometry and moved everything around until it fit in a box.

The internal volume of the woofer enclosure was estimated based on cone displacement and target frequency. I verified my calculations against the enclosure volume of a similar woofer cone available from the manufacture. All of the remaining space inside the case was devoted to storage.

I'm not going to go too far into the electronics here because that would take up an entire instructable of its own, but here are a few points of interest:

• A tweeter is not necessary for a guitar amp. Most, if not all amps do not have tweeters. I decided to include one so that I could use the case as a Bluetooth speaker if I wanted to. The power amp I used has a stereo output which allows me to control the signal sent to the tweeter. By hooking the tweeter up to the left channel and the woofer up to the right channel, I can use the balance knob on my tone adjustment board to bias the woofer when playing guitar.
• I built a second-order Butterworth crossover network into the case to reduce the noise in the woofer and protect the tweeter from the sustained high current signals of lower frequencies.

There are fewer photos from this stage of the project because it went together quickly. The case is almost entirely constructed of 1/2" sande plywood. I cut it manually with a variety of different woodworking tools. The panel where all of the electronics mount and the foam rests for the guitar were laser cut. The battery harness was 3D printed (CNC milling, laser cutting, and 3D printing all in the same project...)

Assembly came down to a lot of wood glue, countersunk screws, and solder. I used a projector to trace the locations of the internal pieces onto the bottom of the case. This aided heavily with alignment and keeping all of the smaller parts accounted for.

This project wound up being significantly more work than I thought it would be. Parts of it (especially the electronics) forced me to learn about things I had never even considered before.

Just the labor hours if I was paying myself at minimum wage would make this guitar worth more than $1000. However, I have no regrets about building it. Playing a guitar that I made myself is infinitely more fun than playing the one I purchased. It makes the music much more personal. All things considered, the guitar sounds pretty good. It is no match for it's professionally built counterpart, but I'm no match for a professional guitarist either.

The case, while on the heavier end, breaks down a lot of the barriers that come with electric guitars. It's one unit that holds my amp as well as my pick, strap, cable, extra strings, ect. I can play it anywhere I can bring it, and when I am not feeling like playing the music I can stream music to it from my phone.

There are plenty of things I would change about this project if I were to do it again, but I am happy with the outcome nonetheless. Here's to the years of music and happiness it should bring!