Tiny Tenor Guitar

The Tiny Challenge got me to return to a tiny guitar project I started about 8 years ago. I was interested in making instruments but I didn’t know much about how to do it. I figured a tiny model would be a good way to start. I’ve since made 11 full sized ukuleles. So I know a lot more about how to put an instrument together, but the tiny scale meant doing things a little differently as you will see.

scraps of nice wood in thin slices. (making acoustic instruments leaves a lot of these)

thread

super glue

wire

Fold a piece of card in half and cut a half guitar shape. If the scale matters to you, measure an existing instrument and divide all your measurements by the same number. Mine is about ⅕ scale. My big guitar is 38” long divided by 5 equals a tiny guitar that’s about 7½” long. Metric measurements are easier to work with tho…

Measure the body of your guitar:
body length: 965mm divided by 5 equals 193mm

width at upper bout’s widest point: 290mm divided by 5 equals 58mm

distance from the top: 75mm divided by 5 equals 15mm

width at waist: 240mm divided by 5 equals 48mm

distance from the top: 170mm divided by 5 equals 34mm

width at lower bout’s widest point: 384mm divided by 5 equals 77mm

distance from the top: 360mm divided by 5 equals 72mm

top to center of the sound hole: 145mm divided by 5 equals 29mm

diameter of the sound hole: 97mm divided by 5 equals 19mm

depth of sides: 100mm divided by 5 equals 20mm

Mark your folded paper as shown. Cut your half shape. See if you like it. If not, do it again until you like your design.

From the scrap pile select enough wood for a top, back and sides. Trace the pattern onto the wood twice for the top and back. For the sides it’s hard to measure how long of a piece you’ll need so err on the side of longer. You can trim it later. Cut out the sides with a bandsaw, scroll saw or coping saw. I think a jigsaw would be too violent (dangerous) at this scale.

For this tiny project I used an old soldering iron to heat the wood. I clamped it to my workbench so I could use both hands on the wood. The wood has to be pretty thin, so I sanded it on my belt sander down to about 2mm thick. It also has to be wet. Get it wet and let the water soak in for a couple minutes. Then put it on the iron and apply a slight pressure to both sides. Nothing will happen at first, but after a few seconds you will feel it start to loosen up. Then you can apply a little more pressure. Have a spray bottle or bowl of water standing by to re-wet the wood. It dries out pretty fast where the heat is applied. When you get the shape close, hold it up to your pattern to see what it needs. I start with the waist, and then the bouts. It takes a fair bit of back and forth between the iron and the pattern to get it all the way there.

Once the sides are bent and trimmed to size, you’ll connect them with a head block and tail block. Then the back can go on. The lining blocks, kerfing and bracing are optional for a tiny model. The purpose of the lining blocks is to reinforce the joint between the sides and back. At this tiny size it’s not really important except for looks. Same with the brace. I put it in to add realism later when peeking through the sound hole.

Use a Forstner or brad point bit if you have one to drill the hole. It will come out the neatest and be less likely to grab and break the top piece. Sand around the inside of the hole to smooth out any splinters or sharp edges.

I used the belt sander for this, but it takes off a lot fast, so be careful not to blast through the sides.

The neck is a little longer than the body. Find a scrap that is big enough to cut out the 15 degree angle at the head, and thick enough for the heel block. I used a Dremel with a sanding spindle to shape the subtle curves on the neck. It requires some finesse. Just go slowly. You’ll need another thin piece to be the finger board. A contrasting wood color is nice.

If you want the fret spacing to look real, use a caliper. I printed out a fret spacing chart from Stewart-Macdonald’s Fret Calculator. You need to pick a scale length, which is the distance from the nut at the head, and the saddle on the bridge. I used 140mm. This put the bridge placement roughly equal distance between the bottom of the sound hole and the bottom of the guitar body. With the caliper, measure out the distance from the nut to each fret, and scratch a line on the fret board. The spaces between the frets get smaller as you go from the nut to the sound hole. I used a chisel and pencil to make the scratches easier to see. Then lightly sawed and filed the slots till they showed up ok.

Line the top of the finger board up just below the place where the head angle breaks. You need room for the nut on the flat part of the neck before the angle.

For the tuning machines I used little pieces of stainless steel wire, and drilled matching sized holes. I tapped them in with a tiny hammer and superglued them in place. For the nut I cut and sanded a tiny piece down to size.

Before gluing on the neck, hold it in place to see if the finger board hangs over the sound hole. If it does, you can mark it and cut it shorter. I used superglue and accelerator and my hands for clamps. The bridge and saddle are so small I just sand little pieces down until they’re the right size. I drilled holes in the bridge and laced the thread in one hole and out the other twice and glued them in place.

Once everything is attached and sanded...

A tiny nail cut short is the strap button. I drilled a hole in the tail of the guitar just smaller than the nail and tapped in through the strap.