Introduction: Cigar Box Three String Guitar
I read a book in the library about cigar box guitars, they looked fun, so I decided to make one.
Poplar from a "Big Box" store: 1 1/2" x 3/4" x 6'
2 brass bolts, 4 brass nuts
thin hand saw
jig saw/coping saw
hand drill w/ bits
guitar parts: 3 tuners, 3 guitar strings, fret wire
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Step 1: Headstock and Neck
First I decided the scale length for this guitar would be 23.5" The scale length is the distance the strings vibrate when plucked or strummed. In this case it is the distance from the "nut" at the top end of the neck to the bridge. The scale length can range from approx. 22 inches to 25 inches. Everything about the instrument is determined by the scale length. There are programs on the internet which give you measurements for fret marks on a particular scale length. I chose an online program which gives a graphical printout so I didn't have to measure each fret mark: http://www.ekips.org/tools/guitar/fretfind2d/
The headstock can be a simple flat design. I wanted a headstock with a receding angle. This is made using a scarf joint. A scarf joint is a special angled cut which, when glued back together, angles the headstock away from the fingerboard surface of the neck at a specified angle (usually about 15 degrees). I think having the headstock angled like this makes it easier to get the strings to stay tight against the nut (this is referred to as the “break angle” of the strings).
Once I cut the scarf joint, I laid out the curves I wanted and cut these with a coping saw. Then used a rip saw to 5/8" so the posts of the guitar tuners would extend far enough through the head stock when mounted later on.
The next step was to glue and clamp the head stock back onto the underside of the neck.
Step 2: Fret Board
My next step was to add slots on the fret board. The fret board was an additional piece of poplar, 1/4" thick. I trimmed it to match the width of the neck and the length of the paper fret scale template. I taped the paper scale to the fret board, noting that the 0 fret was the "nut" location. I used a utility knife to mark the fret board by piercing the template on each fret line. It is important to do this as accurately as possible. Next I placed the board in the miter box, using my thinnest saw I cut 1/8" into the board on the knife mark.
Step 3: Fitting the Frets
After the fret board was slotted, I stained it. Then using purchased, medium, nickle fret wire I pressed the wire gently into the slot. Next the wire was trimmed with nippers and the fret was tapped into the slot until it was firmly seated. Next the sharp ends and edges of each fret had to be filed smooth so the players fingers would not be cut when moving quickly up and down the neck. I took my time and was careful not to gouge the wood.
Step 4: Fitting the Neck
Before the fret board is attached to neck, it has to be fitted to the box. I used a coping saw to remove a notch out of the sides of the box which allow the neck to pass through the box. I carefully placed layout marks on the neck to be the starting point of all measurements based on the previously chosen scale length. My choice was 23.5 inches. I tapped the paper template on the neck being careful to check the placement of the 0 fret on the head stock. This is where the "nut" will be placed later. When I was sure of this reference point, I marked it on the headstock. From this mark, I measured down the neck the length of my chose scale length, which is 23.5 inches. I placed a second layout mark on the neck at this spot. This is where the pressure from the bridge will transfer through the box lid to a support on the neck. Then I repeated the measurement from "nut" to the end of the scale length, 23.5 inches, finding the same spot this time on the surface of the cigar box. I marked this with a third layout line on the top of the box. The bridge will rest here.
Once this measurement were checked three times, I lined up the second and layout lines mentioned above. This means I lined up the place where the bridge will rest (23.5 mark on the lid) with the bridge support mark (23.5 mark on the neck.) Holding the neck in place, I placed a layout line where the inside of the box meets the neck.
These last layout marks are the limit of what I then trimmed off the neck. I used the table saw set to approx 1/8" to remove material from the neck, starting at the layout marks but being certain to keep the material at the bridge support. In the picture above the red pencil shows the resulting bridge support, as well as the corresponding bridge mark in the lid.
When all the fine fitting was completed with chisels, I glued the fret board onto the neck, making certain the 0 fret mark for the nut lined up exactly with the reference mark on the headstock.
To finish this step I added a hinge to the protruding tail of the neck, and cut sound holes in the lid with spade bits.
Step 5: Finishing Up
I used a scrap of wood (walnut) as the base for my bridge. I found brass bolts and nut to be the bridge and nut on my guitar. I used a hack saw to remove the hex head of the bolt. Then I super-glued the nuts in place on the bolt. I did the same thing at the 0 fret on the headstock. Corner screws hold the lid on and the pressure of the strings keep the bridge in place.
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