I decided to make a slightly fancier guitar than most, with real guitar tuning pegs, a nice stained and varnished finish, and a piezo pickup. You might see some photos of my homemade banjo, since I built both around the same time.
A little history: cigar box guitars have been built since the time of the American Civil War, but they first took off in popularity during the Great Depression of the 1930s. Blues musicians especially favored the small guitars, along with cookie tin banjos, washboards, and other improvised instruments. During today's economic woes and the rise of the DIY and Maker movements, musicians and hobbyists have revived the art of building and playing cigar box guitars.
Step 1: What You'll Need
~Cigar box - $1
I got this one at a garage sale. If you make friends with a cigar smoker or tobacconists you can probably get this for free.
~1" x 2" x 3" poplar board - $3
keep in mind that these are actually 3/4" x 1 1/2"
~Guitar tuning pegs (3) - $4
These usually come 6 to a pack for about $8, so you can make another guitar with the other three!
~Guitar strings (3) - Free!
I had some old nylon strings lying around, so I used the low E, A, and D strings. You can also use fishing line, steel wire, or plastic string
~Copper sheet metal - Free!
This is used to make the tailpiece, the part that holds the strings on the bottom. I found some while dumpster diving at a construction site. You could cut apart a tin can if you can't find copper
~Wood glue - $3
~Wood stain (optional) - $4
You can use any color; I choose a reddish brown. A little can'll do ya!
~Spray varnish (optional) - $5
I used semi-gloss.
~Piezo buzzer and guitar plug (optional) - $4
This gives you an electric cigar box
~Coping saw or jig saw
~Drill with bits
~Rough file or rasp
~Sand paper in various grits
I used between 60 and 400 grit, although 100 and 200 would work fine
~Clamps (or heavy things)
~Various hardware (screws, small finishing nails, etc.)
~Soldering iron (for connecting the piezo buzzer)
Step 2: Cut the Cigar Box
Once you've picked a side to cut, measure and mark the center of that side lengthwise. Make marks 3/4" on either side of this mark. Measure and mark 3/4" from the top of the box (or the bottom; whichever side you want to be the front of your finished guitar). Connect these marks with a ruler to make a 1 1/2" by 3/4" rectangle, in the center of one side and right against the top of the box. Cut out this rectangle and test fit the neck. The hole should fit horizontally but be too small vertically by about 1/8", or the thickness of the top of the box.. We will account for this in the next step by cutting a notch in the neck.
Now it's time to cut sound holes in the top of the box. You can simply drill some holes with a hole saw, but I wanted some stylish f-holes, like a violin. First I printed off a picture of a violin and taped it to the top of the box, being careful to center it as well as I could. Then I drilled out the top and bottom of each opening, and connected them using the coping saw. A thin blade and a lot of patience helps here. You can finish off any rough edges with a file or sandpaper.
Step 3: Notch the Neck
Optional step: I added a heel where the neck meets the body, made from scrap pieces. This is even with where the cutout begins, but on the opposite side of the neck. I glued the blocks of wood to the neck and roughed out the shape with a saw and file after the glue dried.
You will also want to round out the back of the neck, to make it easier to slide your hand up and down. This can be done with a rough file or low-grit sandpaper. It doesn't have to be perfectly rounded, just smooth enough to be comfortable.
Now start sanding! Especially on the back side of the neck, you want the wood to be very smooth. I also wanted to make a nice and shiny guitar, so I went all the way up to 400 grit. Unless you have a power sander this will probably take a long time.
Step 4: Carve the Tuning Head
For spacing the strings, measure and mark every 7.6 mm across the neck. You can calculate this with the following equation: string spacing = width of fretboard / (number of strings + 2). Now you can start to lay out the shape of the head and the position of the tuning pegs. If you have individual tuning pegs, you can make whatever shape of head you want. With the three-in-line tuning pegs I have, I decided to do an angled head so that each tuning peg lines up with its respective string. You could also use a violin-style tuning pocket. See the picture below for a general view of the head layout I used. Drill holes all the way through the head for the tuning pegs, being careful not to knock any chips out the back. Don't be too worried though; the tuning pegs will cover up a lot of imperfections.
Now it's time to cut out the head. I used an electric jigsaw, but you could use almost any kind of saw that is capable of making small-radius cuts. Be sure to keep everything square and level.
Step 5: Stain and Finish
After sanding you will need to wash off any sawdust before applying the stain. Wet the wood with the stain thoroughly and wipe off any excess before letting it dry.
My guitar is fretless, but I used a Sharpie to add fret markers to the neck. This wasn't the best choice, since the clear coat caused the lines to run a bit. You could probably use some acrylic paint instead, or some countersunk nails to mark the frets. There are many other ways of making frets if you want them; I've seen cigar box guitars with nails and wooden matches for frets.
Spraying on the clear-coat is best done in a well-ventilated area, and a face mask doesn't hurt either. Hang up all the pieces with wire or string and add thin layers slowly to prevent runs. When the first layer is dry you can wet sand with a high-grit sandpaper, then spray a second coat.
Step 6: Tailpiece
I used the same string spacing as on the neck and tuning head to space the three holes at the top of the tailpiece. Then I scribed a symmetrical triangle with a pocket knife and marked another hole at the point. After cutting out the triangle I rounded off the corners with tin snips and a file. Then I punched out the holes with a nail.
Bend the tailpiece so that doesn't quite touch the top of the box, and be sure to de-burr the holes since sharp edges will lead to broken strings.
Step 7: Screwing It All Together (and Make It Electric!)
Before closing up the box, attach a piezo pickup if you are using one. This is really just a piezo buzzer from Radio Shack soldered to an output jack. I'm not sure what the best method of attaching the piezo is, so I just nailed it in there with a couple small tacks. You'll need to drill and countersink a hole in the box somewhere for the jack to pass through. I keep the box closed with a few staples opposite the hinges so that I can open it back up easily, but you can also simply glue or nail it closed.
Screw on the tuning pegs and tie on the strings. After you get some tension in them you can add the nut (at the top) and the bridge (at the bottom) and they will stay put without any glue. Drive three small nails into the head right above the nut and hook the strings under the nail heads to provide downward tension on the nut. I used a small nail for the nut and part of a bamboo chopstick for the bridge.
The tuning I prefer is D-A-D, or the bottom three strings of drop-D tuning. Feel free to experiment with tuning, since there is no "standard" tuning for three-string guitars.
Step 8: Play!
Below are a couple mp3's to show what my guitar sounds like, and a video demonstrating some of its features. At the end you can see my version of "Save Me" by Seasick Steve (who plays the blues with his one-string diddley bow and his three string guitar).