$150 Custom Ergonomic Guitar

Do you have basic woodworking skills? Can you strum a chord? If so, you can build a custom ergonomic guitar.

I started playing electric guitar about a year ago, and quickly grew frustrated with the ergonomics of the seated playing position. With a traditional electric guitar (Les Paul Special, in my case), the neck is more or less horizontal. This causes the right shoulder to be raised, and the left wrist to be excessively bent. The right leg is usually propped up too, causing uneven sitting pressure.

An ergonomic guitar is designed to balance on the leg with a more upright neck angle. This is done by moving the cutout and either reducing head stock weight (see headless guitar) and/or adding material to the tail end of the body. The result is a playing position with minimal strain on the shoulders, back, or legs, as well as better access to the fret board.

http://buildingtheergonomicguitar.com/ Is a great resource and showcases various ergonomic solutions.

Still interested? Read on.

Materials

I had done very little guitar setup work, and had no luthier experience prior to this project. I also did not want to spend hundreds of dollars on custom parts and hardware. Finally, I had only two weeks to complete this project. The materials reflect these constraints.

The cheapest and easiest way to acquire the parts needed to build a guitar is to harvest them from a donor. I purchased an Epiphone Les Paul Special P90 for about $100 from the local Guitar Center. Using a donor guitar also gives you measurements for bridge and pickup location, as well as neck pocket angle.

The only piece of hardware I did not use from this guitar was the wraparound bridge. I replaced it with a Tune-O-Matic style bride/tailpiece for less than $10 on Amazon.

The body of the guitar is made from two 3/4" birch plywood boards glued together.

Paint is Rust-Oleum Painter's Touch 2X. I used about 2 cans of color and 2 of clear.

Tools

The power tools I used were a router, a jigsaw, and a belt sander (optional).

For the router, you will need a pattern following bit (straight cut, with equal diameter ball bearing on shank) and an inlay kit (router base bushing and straight bit).

A drill press would have been nice, but I did fine without one.

For the electronics, you will also need a soldering iron and a pair of wire strippers.

Safety

POWER TOOLS ARE DANGEROUS!!! Improper and unsafe operation can lead to severe injury, an expensive trip to the ER, and/or permanent loss of fingers or sight.

- Do not work while tired. The greatest safety guard is your mind.

- Always wear safety glasses. Get a nice pair that you won't mind wearing at all times.

- Make sure your workpiece is secured properly, preferably by multiple clamps or a good vise.

- Always unplug power tools while changing blades/bits

- Protect your lungs from sawdust and paint fumes. Work in a well ventilated area and wear an appropriate mask. I recommend purchasing a decent respirator. Potential medical complications cost much more than any safety equipment.

Check out http://buildingtheergonomicguitar.com/ and get your creative side going. We all know guitars are as much visual as aural.

Once you have a general idea in mind, make a couple of cardboard templates. These should give you a good idea of the strumming position and neck angle.

Once you've settled on a design, cut a template out of 1/4" plywood using a jigsaw. Rough sand any imperfections, as these will be transferred onto the body when the router follows the template. A little work in the beginning saves a lot of work later on.

Now is a good time to figure out where you want the control knobs, electronics cavity, output jack, and other features to go.

Throughout every step of this project, make sure you keep track of the centerline. This is very useful for measuring out other features, such as wiring routes.

Trace your template twice onto a sheet of 3/4" plywood, then cut out with a jigsaw, leaving about a quarter inch of extra material. I ended up leaving more material on than needed, which created excess work for the router.

Again, make sure you keep track of the centerline. I also marked two cross-lines, which were used to align the two halves.

This is where planning ahead is crucial. Making a guitar body from two plywood sheets allows us to route the wiring paths prior to gluing. This is much simpler than trying to angle a drill properly.

Spread wood glue evenly on the two halves then use as many clamps as you have to hold them together.

Once the glue has dried, attach the template to the rough cut body using double sided tape. Carpet tape works well. The template will likely have to be raised 3/4" above the blank for the first pass - spare plywood and more carpet tape works fine. Follow the template with the router. Be careful not to let the cutting edge of the router touch the template on the way on or out - any imperfections in the template will transfer full depth to the body.

Sand the edge after routing. A drum sander would've been very helpful in smoothing the edge, but I did fine with a $20 belt sander, and of course, plenty of hand sanding.

This is one of the trickier parts of guitar building. The neck pocket is tapered and angled back by about 1.5 degrees.

My routing jig was based off the design here http://www.mykaguitars.com/tools/neckpocketjig/

The neck angle and height drop over the jig can be determined by measuring the donor guitar body with a depth gauge and some basic trigonometry. I think mine was around a 0.6" drop over 24" span.

Conventional wisdom says the neck pocket should be snug enough for the neck to support the body without any fasteners. I think this may be true for set necks (glued), but not so much for bolt on necks. The most important surface contact is the bottom of the neck, as this will be drawn to the body with the screws. In my case, I realized the neck pocket was too tight after final assembly - there's a very slight gap underneath, and the outward force from wedging the neck in actually caused the top plywood layer to shift slightly in relation to the bottom half.

I started by drilling the output jack recess with a spade bit. I don't have a vise, so I just clamped the body to the table laid on it's side for this step.

The electronics cavity was roughed with a spade bit, then freehand routed. The slight recess to accept the plastic cover was routed with a template, though I still needed to sand the cover to get it to fit.

Pickup cavities were also routed with a template - keep in mind they're at different depths.

For installation of the Tune-O-Matic bridge and stopbar, I followed the instructions in this video

I recommend buying bolts that thread into the posts (M6 and M8 worked for the hardware I got). These can be used to tap them into the guitar and also aid in removal for painting.

The drill size will vary depending on the post size. I recommend testing the post to hole fit on a scrap board, so the posts can be hammered out from the bottom if they're too tight. My local hardware store didn't stock drill bits in 1/64" increments, so I had to go with a slightly smaller drill for the bridge posts and wiggle the drill around to enlarge the hole slightly.

I also recommend using transfer punches, as recommended in the video. I didn't, and my bridge post holes had to be enlarged, so I could shift the mounting posts slightly and get the bridge to slide on.
Finally, make sure to drill a cross hole from the tailpiece post hole to the electronics cavity for a string grounding wire.

Spread wood filler all over the guitar body with a putty knife or cheap chisel. Plywood has many voids that are very obvious on the edge. The wood filler can also cover up mistakes, such as my grain splitting while drilling the pickup selector hole.

Painting. Blegh. I don't have any photos of this process because I was simultaneously excited to finish the project and terrible at spray painting. I made several mistakes, requiring multiple standings and reapplications. Here are some things I learned:

- I went with a satin/matte finish. If you want a deep gloss, there are countless resources on paint selection and surface prep by more qualified posters.

- Mask off the neck pocket if the fit is already snug.

- Spray paint is pigment mixed with solvent and a propellant. "Drying" occurs when the solvent evaporates out, and takes less than an hour. "Curing" takes much longer, up to a month. Until the paint is fully cured, the surface is pretty soft and vulnerable to indentation.

- If you apply spray paint too thick, it will run. Don't do it, even if you're just trying to build up some thickness to sand down. The outer surface of the paint will quickly dry, trapping the solvent under it and causing a ridiculously long drying time. If you try to sand drips before the paint is completely cured, you'll find the paint is softer below the outer layer, and can't be effectively smoothed (your paper will clog).

- If you apply spray paint too thin (holding the can too far away, not overlapping sprays), it will cause a rough "orange peel" finish. This is caused by the paint particles clumping in the air, and too much solvent evaporating before the paint is on the surface. The paint must wet the surface in order for it "flow" and flatten out. Gotta find that happy medium...

- If you can't get a decent surface finish with the color paint, don't worry. I ended up sanding with 400 grit, then starting the clear coats. For some reason, the clear coat flows much better than the color paint, and is much more forgiving of thick application.

The post and electronics holes may need to be re-drilled to remove paint buildup. It's a good idea to pre-drill the output jack and electronics cavity cover screws with a wire-size drill. I used regular speaker wire to connect the electronics cavity to the output jack, and haven't noticed any more EM interference, compared to a stock Les Paul.

Overall, this was a very fun project. I'm not a luthier, nor am I a halfway decent guitar player, but I managed to make a playable guitar. Does it sound like a Gibson? Probably not. Can I tell the difference? Nope. My hunch, however, is that electric guitars are fairly forgiving, given the various physical and tonal adjustments possible. As long as everything is in the right place, you should have a decent instrument to practice on.

Thanks for reading this Instructable. If you have any questions or suggestions, please let me know.