Build a Semi-hollowbody Electric Guitar

This instructable will show you how to build a bolt-on neck, semi-hollowbody electric guitar, in the manner of Fender's Thinline guitars and similar. The body I made is similar to a Jazzmaster or Jaguar, with a flat top, but the steps would be the same for any body shape and for carved-top bodies. Using the same woods and similar hardware as I did will get you a guitar that weighs total ~7lbs (my neck is a 1-piece maple, so it's a bit heavier than a mahogany neck wood be; the body itself weighs right at 4lbs). The look--natural mahogany back, lightly dyed top, natural binding--was inspired by the Les Paul in the pics.

Some of the pics show something different was done than I describe in the steps, and that's because some of the things I tried didn't work out as planned.

A warning, before we get into it: this is an addicting hobby. Don't blame me if you come to yourself in a couple months and find yourself with a pile of guitar bodies you have no use for. :)

Materials

• 1/2" x 2' x 2' pressboard
  For the template
• Back wood: 6/4 (1 1/2") hardwood, 2 pieces, 8 x 20" (or 1 piece with the combined dimensions)
  I used mahogany, but ash, maple, alder, walnut, etc. (any hardwood) will work. Unless you're going to paint it an opaque color, I'd avoid less visually-appealing hardwoods like poplar or basswood.
• Top wood: 2/4 (1/4 - 3/8") hardwood, 2 bookmatched pieces, 8 x 20"
  As with the back, any hardwood will work; traditionally for this you'd use maple, which I did, but as long as it looks good, go with whatever. If you're painting it a solid color, the look doesn't matter; otherwise, make sure it's bookmatched--this is when a thicker piece is split into 2 thinner pieces and planed smooth, so that when you "open" the thicker piece the grain pattern matches up from the join line. If you buy your top wood from a lumber supplier that specifically sells guitar wood--Stewart MacDonald, Luthiers' Mercantile, many others online--will have this available. If you're going to carve the top--like on a Les Paul or PRS--you'll need thicker top wood.
• A bolt-on neck with a standard Strat heel (this is the default for almost all replacement necks)
  I got mine, a 1-piece birdseye maple neck, from Warmoth. If you want to have custom options (fret size, fancy neck/fingerboard woods, inlays, etc., you'll need to buy from a built-to order place; if you just want a bog-standard Strat or Tele neck with maple or rosewood fingerboard, you can get them relatively cheap online.
• Wood glue
  I use Titebond, but there are a plethora of brands that will work just as well. Do not--DO NOT--use Gorilla Glue. It expands as it dries and can mess up your joins, as well as being a huge pain to clean off of the exposed surfaces. Standard wood glue is plenty strong for what you're doing here.
• Shellac or grain filler
• Dye or stain
  I just use liquid Rit dye, diluted with water to get the desired shade; it's also easily mixable with other colors if you want a fancy color (blue + green + water = seafoam green, for example)
• Clear spray finish
  I used Minwax lacquer; this is about as close as you can get to traditional nitrocellulose lacquer used by guitar manufacturers back in the day without paying an arm and leg. Polyurethane or shellac will also work, with some application technique differences.
• Liquid car polishing compound
• Car wax/polish applicator and applicator pads
• Wire hanger
• Painters tape

Tools

• Bandsaw or jigsaw
• Router and assorted bits
  
  • 1/4" and 1/2" top-bearing pattern bits
  • 1/4" bottom-bearing pattern bit
  • 1/8" and 1/4" roundover bits
  • 1/4" straight bit
• Drill and assorted bits
• Drill press
  Not required, but makes some steps easier to get right
• Hand sander and drum sander bits for drill press
  Not required, but makes sanding a heckuva lot quicker & easier
• Sanding block
• Sandpaper: 80, 120, 220, 1000 grits
• 0000 oil-free steel wool
• Files
• Clamps
• Soldering gun and solder (for wiring)
• Routing templates for neck pocket, bridge (if using a tremolo bridge), and pickup cavities
  I got mine from Stewart MacDonald; they're relatively cheap, and well-worth avoiding the headache caused by a routing screw up
• Double-sided tape
• Tack cloth
• Disposable rubber gloves

Guitar Parts
You need to have all of your parts (excepting pickups and electronics, as long as you know what style you want) before you start

• Pickups
  I'm using 3 Strat single coils
• Pickguard
  Optional, but I like the look of a pickguard on Fender-style guitars. You can get pretty much any standard pickguard shape with custom options from places like Warmoth; if you're using the standard options, the internet's full of 'em
• Bridge
  I'm using a Strat-style tremolo bridge; for this body style, any kind of flat-top bridge will work. If you want a Les Paul-style tunomatic bridge, that can work, too, but you'll need to shim the neck pocket to angle the neck slightly to account for the bridge height.
• Strap buttons
• Screws for everything

Back

1. If necessary, plane and/or sand the joining edges smooth
2. Put glue on 1 of the edges and push the pieces together
3. Place a thin piece of scrap on the top and bottom of the joined piece, over the center line, and clamp them vertically
   This reduces the amount of leveling needed afterwords
4. Clamp the pieces together horizontally in at least 3 places
   The more clamps, the better. You want a little squeeze out, but don't over-tighten and squeeze it all out; rule of thumb: if your clamp bar starts bending, it's too tight
5. Let it sit for a couple hours and remove the clamps, then let it sit for a couple more hours
6. Plane and/or sand it smooth and level
7. If you have any gaps in the join, flood them with superglue and immediately sand over the join to fill them

Top
If your top wood is thick enough to clamp together, just use the same steps as for the back wood

1. If necessary, plane and/or sand the joining edges smooth
2. Push the pieces together as tight as you can by hand
3. Put a strip of painters tape over the join to keep them together
4. Flip the joined piece over and "open" it slightly
5. Put glue on the edges and push the pieces back together by "closing" it
6. Wipe off the glue squeeze-out
7. Put another piece of tape over the join line to "seal" it
8. Set something(s) heavy on the joined piece to keep it flat while the glue dries
9. Let it sit for a few hours
10. Plane and/or sand it smooth and level
11. If you have any gaps in the join, flood them with superglue and immediately sand over the join to fill them

1. Figure out what you want your body to look like, dimensions, etc.
   Highly recommend using existing blueprints, which can be readily found online (for example), as a starting point. That takes a lot of the guesswork out of it, so you can just tweak the outline to your liking. The one I made is mostly Jazzmaster, with a bit of Telecaster in the dimensions of the upper horns, and a "cut-out" on the bottom just because I think it looks cool
2. Draw your desired body shape to scale on foam-board
3. Cut it out as cleanly as you can
4. Trace the outline onto the pressboard with a thick-tip sharpie
5. Cut it out with your bandsaw or jigsaw
6. Sand the edge smooth
7. Mark the center line:
   1. The easiest way to do this is by starting with the neck pocket area, which is 56mm wide
   2. From the edge of the neck pocket, measure 28mm over in 2 places, and mark it
   3. Draw a line through the 2 points all the way down the body
8. Mark the center "beam" for the body:
   1. Measure the width of your bridge, and add an inch
   2. To either side of the center line, measure out half that value and mark it in at least 2 places
      For example, if the width + 1 is 3", measure out 1 1/2" from the center line, on either side
   3. Draw a line through the points on either side
9. Approx. 1/2" from the outer edge, draw a line all the way around the body
   This is your outer wall
10. On the right side of the body, draw a 1/4" line set approx. halfway down
11. On the left side, draw a 1/4" line set approx. 1/3 of the way down
    This gives you the 4 hollow pockets; see the pictures for steps 10 & 11 to make more sense. This isn't strictly required, you can just have 2 (which is how Fender does it) but it gives you more gluing surface and body strength later on, which is my preference
12. Drill a pilot hole for the router bit in each pocket
13. With the 1/4" straight bit, route out the pockets
    Route clockwise when routing on the interior of a template, and do it in multiple passes so you don't get tear out
14. Sand the interior edges smooth
15. Drill 2 screw holes all the way through the template on the center line
    Do 1 in the neck pocket area, and one roughly where the bridge will be; this is to attach the template to the body blank
16. Use a 1/4" forstner bit to drill partway through the template--1/4" will do--so the screws will sit below the template surface
17. With a 1" forstner bit, drill a hole at 2 points along the center line
    This is for aligning the template with the center line of the body blank

1. Line up the template with the body blank center line and screw it down
2. You can make this step a little easier by using a bandsaw or jig to trim off the excess body wood
3. Drill a pilot hole all the way through for the exterior perimeter, and another, not all the way through, in each of the interior pockets
   You want to leave about 1/4" of thickness in the interior pockets, so set your drill depth accordingly
4. With the 1/2" pattern bit, route out the body and pockets
   Do multiple passes (obviously), no more than 1/4 - 3/8" at a time; doing more risks tear out/wood burn. Routing the outside perimeter, route counter-clockwise; for the interior routes, go clockwise. Be sure to let the bit stop spinning completely before lifting it out, or you risk dinging your wood and/or template (see pics)
5. Remove the template once the top-bearing bit can go no deeper without the chuck hitting the template, and use the already-routed edges as the guide
6. The interior pockets should be able to be finished this way, but you'll probably need to switch to a bottom-bearing pattern bit and flip the body to finish routing the exterior edge
   Make sure you set the bit deep enough, or you'll get a burn line (see pics)
7. Sand the exterior edge smooth
   You can do this by hand with the hand sander, but it's much quicker and easier with the drum sander attachments for a drill press
8. (Optional) Drill some holes in the sides of the pocket support bars to increase the resonance
9. Apply glue to the top side edges
10. Place the top wood on to the back wood
11. Line up the center lines (the join lines) and clamp them together
    Make sure they stay aligned; you'll probably need to readjust a couple times
12. Place something heavy in the center of the top to press it down and prevent it not getting glued down
13. Let it sit for a couple hours, then remove the clamps
14. Let it sit for a couple more hours
15. With the bottom-bearing pattern bit, trim the top wood to match the back wood
    It should now look like a proper guitar body
16. With the 1/4" roundover bit, route the roundover on the back
    Not on the heel; do that with the hand sander, to about 1/8", and blend it into the large
17. Sand the edges smooth, to 220 grit

Neck Pocket

1. Measure 3" down the center line from the top edge of the neck pocket area, and mark it
2. From that mark, measure 28mm left and mark it
3. Align the neck pocket routing template with the center line and these 2 marks, and attach it to the top using double-sided tape
4. With the 1/2" pattern-bit, route the neck pocket to a depth of 5/8"
   Multiple passes, clockwise routing, be careful not to ding your template when lifting the router

F-Hole

1. Decide on your f-hole shape, and draw it onto the top
   An f-hole can be as simple or fancy as you want: traditional stylized "f", a couple round holes, a lightning bolt... Just make sure to locate and size it so you don't hit the exterior wall, center beam, or bridge
2. With the 1/4" straight bit, route out the f-hole
   Clockwise routing, 1-pass should be good; be very careful, it's super-easy to screw up the top irreparably with a slip-up here
3. Clean up the lines by hand with files and sandpaper

Pickups/Pots/Switch

1. Put the pickguard in place and mark the pickup, control, and screw locations
2. Align your pickup template with the center line and marked locations, and route the pickup cavities with a top-bearing pattern bit
   For pickup types that hang from the pickguard (single coil, humbuckers, mini-humbuckers), go as deep as you want; for pickup types that attach to the body directly, measure the thickness of the pickup and route accordingly. For body-attached pickups, standard routing depths can be found online
3. Use a 1" forstner bit to route the output jack hole
4. Use 1 1/2" forstner bit to route the pot holes
5. With the 1/4" bit, route a 1/2" connecting channel between the holes
   Make sure to leave plenty of wood around the pickguard screw holes
6. With the same bit, route a hole for the selector switch, and a connecting channel to the neck pickup cavity
   If you're using a toggle switch, you can just drill the hole with a forstner bit

Bridge

1. Measure your neck from nut to the 12th fret; double that length to get the neck's scale length
   Scale length = the distance from nut to the bridge saddles
2. Measure the neck from nut to the bottom edge
   This is the fingerboard length
3. Subtract the fingerboard length from the scale length
   This is the distance from the bottom edge of the neck pocket to the bridge
4. Measure that length down the center line from the bottom of the neck pocket, and mark it
5. Align the top bridge routing template to this mark and the center line, and attach it
6. With the 1/2" pattern bit, route the cavity as deep as you can
   When the bit can go no deeper without the chuck hitting the template, remove the template and use the already-routed wall as the guide
7. When the bit will go no deeper, drill a pilot hole all the way through the body in the center of the cavity
8. Flip the body and complete the through-body portion with the bottom-guide pattern bit
9. Align the bottom bridge routing template with the center line and the cavity's top edge, and attach it
10. Switch back to the top-bearing pattern bit, and route the cavity to a depth of 1 1/4"
    The cavity will be longer on the back than at the front; this is by design, so the tremolo block will be able to pivot when engaged
11. Route the other portion of the template to 1/2"
    This is for the springs and spring claw
12. Position the back cover plate and mark the screw locations
13. Mark the spring claw screw locations

Drill Various Holes
Screw sizes will vary based on your parts; my pickguard/back plate screw are #4, bridge mounting screws are #6, spring claw screws and #8, and neck screws are #10. Recommended pilot hole sizes can be found here.

1. Drill pilot holes for the pickguard screws
2. Drill pilot holes for the bridge mounting screws on the top
   It is vital that these are aligned correctly; if not, the tremolo won't work properly, up to snapping the screws off when you attempt to engage it
3. Drill pilot holes for the back cover plate
4. Drill pilot holes for the spring claw
5. Drill a 1/4" hole from the bridge spring cavity into the control cavity
   This is for the bridge ground wire
6. Drill pilot holes for neck screws
   I drill these 1 bit size larger than recommended (3/16 instead of 9/64), to reduce the torque when mounting the neck; there's still enough "bite" to keep the neck in place, but the chances of snapping/stripping the screw are reduced. Templates for neck screw drilling can be found online. I'm not using a mounting plate, so I countersunk the screws and used washers.
7. Drill pilot holes for the strap buttons at the peak of the top-left horn and the center line at the bottom
8. I like a thinner heel, so I routed down about 3/8" around it, and blended it into the rest of the back with a round bit
9. Because I'm using a Jazzmaster pickguard, and Jazzmasters typically have a tuneomatic-type bridge mounted on the pickguard, I also had to reshape the pickguard a bit to fit the Strat-style bridge

You can skip to the next page after step 5 if you're not using an open-grained wood for the back. The goal of this section is to fill the grain so you can get a smooth clear coat later, and to keep the stain/dye in the next section from penetrating the top wood on the side so we get a "natural binding."

1. Sand the entire body to 220 grit
2. Wipe it down with a tack cloth
3. Make a shellac applicator:
   1. Ball up a ~6x6" piece of fabric, like a cut-out from an old t-shirt
   2. Place that in the center of another similarly-sized piece
   3. Twist the corners of the 2nd piece together
   4. Put a rubber band over the top to keep it together
4. Apply shellac to the back and sides
   Work quickly, in circular motions. Shellac dries quickly, so avoid going back over an already-done area or you'll get ripples
5. Let it dry for about an hour
6. Sand it back to bare wood
7. Repeat steps 4-6 until the shellac coat is smooth
   The point here is to fill the grain; sanding it back leaves the shellac down in the wood's pores, so after a couple (or more) rounds of this, you'll get a perfectly smooth-to-touch surface.
8. Apply 1 last coat of shellac to seal the wood

1. With painters tape, cover the sides and back of the bridge cavity
2. Stuff the control, bridge, and f-hole cavities with crumpled newspaper
3. Make another applicator, the same way as the shellac applicator in the last section
4. Wipe down the top with just water to raise the grain
5. Sand the top smooth again with 220 grit
6. Mix up your dye
   I'm using liquid Rit, fuchsia; my initial mix was about 1/4 cup dye and 2/4 cup water. If you're using a darker color for your final shade--dark red or blue, something along those lines--use black dye for this step, and switch to your final color on step 9
7. Apply the dye to the top, and let it dry
   Drying will take about 20-30 minutes, or you can speed it along with a heat gun. If you use a heat, be careful not to scorch the wood or melt the tape
8. Sand the top again with 220, until color is left only in the "flames" (or as close as possible)
   This will make the grain "pop"
9. Dilute the dye further; my final mix was 1/4 cup dye to 3/4 cup water
   It's better to go too light than too dark; one is much easier to fix
10. Apply the dye and let it dry until you reach the desired final shade
11. Go over the top with tung or teak oil
    This will darken your top color slightly, but it also has the more important benefit of increasing the flame contrast
12. Lightly sand with 220 (or higher, if desired) until the top is smooth
13. Remove the tape
14. With the 1/8" roundover bit, route the top roundover
15. Sand the roundover smooth with 220
    It's best to do this by hand, so you don't accidentally eat into the shellac or dye

The clear coat instructions are for lacquer; if you're using something else, follow the application instructions on the product.

1. On the inside of the neck pocket, screw in a neck screw partway
2. Go over the whole body with steel wool, then a tack cloth
   Make sure to get out any debris sitting on the newspaper in the cavities, too
3. Bend a wire hanger to make a body hanger, and hang up the body
4. Spray the whole thing with clear coat, 1 trip down and 1 trip up per side
5. Let it dry for at least 30 minutes
6. Apply another coat
7. Let it dry for a few hours
8. Go over the whole thing with steel wool, and tack cloth it off
9. Repeat steps 4-8 until you reach a finish thickness/shininess you're happy with
   I used 3 cans of spray lacquer, about 12 coats
10. Let it hang and dry for at least 24 hours

1. Fill a rectangular dish with warm water and a couple drops of dish soap
2. Put a piece of 1000 grit sandpaper onto a sanding block and let it soak while you do the next step
3. Put towel (or any other soft cloth) down on your work area, and make sure you have good lighting on the body
4. Wet sand the top, 1 section at a time, all in the same direction
   Keep the paper wet, and rinse it by swabbing through your soap water every few strokes so you don't get build up on the paper. If you start to get a lot of drag, even with the paper wet and clean, change to a new piece of sandpaper--probably need 1 piece each for top, back, and sides.
5. Wipe down the top with a clean cloth
6. Repeat step 14-15, sanding in a different direction
7. Do this until the finish is uniformly smooth and dull
8. Repeat for the sides and back
9. Squirt polishing compound onto the top, like you would if waxing a car
10. With a clean car wax applicator, go over the top until shiny and scratch-free
    This will take 3-4 passes: the 1st, go left to right, 2nd, up and down, 3rd and 4th, circular. Apply more polishing compound between each pass, and also if you start to get drag on the applicator
11. Repeat for the back and sides
    For the sides, I found it works better to apply the compound sparingly directly to the applicator
12. Wipe all surfaces down with a clean rag
13. Apply guitar polish, and buff it with a clean wax applicator
    For the initial polish, you'll need to do this a couple times, as with the polishing compound. Keep going until you get it as shiny as you want, or as shiny as it'll get
14. Wipe the body down again with a clean rag

I'm not going to go too in-depth here, because this depends a lot on what hardware you've got.

1. Attach the neck
2. Install the bridge:
   1. Insert it into the through-body cavity
   2. Line up the mounting holes and screw it down
      Leave the screws out about 1/8", so the bridge can move when the tremolo is engaged
   3. Attach the bridge ground wire to the spring claw
      Give yourself plenty of wire length to work with
   4. Mount the spring claw, screwing the screws in just enough to keep it attached
   5. Run the ground wire through the hole to the control cavity
   6. Insert the spring posts into the tremolo block
   7. Attach the spring hooks to the claw
   8. Tighten the claw screws until only about 1/4" of screw is exposed
3. Install the pickups, pots, jack, and switch onto the pickguard
4. Wire them up
   This article has a good overview for guitar electronics soldering, and diagrams for almost any wiring scheme can be found here. I included the diagram I used in the pictures.
5. Install the pickguard
6. Install the knobs
7. Install the strap buttons
8. Perform a set up
   This instructable has instructions for everything involved
9. Jam!