Step 1: Material List
The size of the parts vary with your own individual design. And the meassurements are all in millimeters(mm). If you need it in inches, you have to multiply the millimeters with a factor of 0,03937. So 1mm equals 0,03937 inches.
What to buy(more or less):
2 x thin wood lathes (60 x 5 x 100)
1 x thin wood lathe (10 x 20 x 100)
1 x thick wood lathe (60 x 20 x 100)
1 x thin large sheet of chipboard
2 x sticks (diameter = 10mm, length = 1000mm)
4 x strings
4 x machine heads for the strings
14 x frets
If you're not familiar with the metric system, here's a little cheat-list:
1 meter(m) = 100 centimeter(cm)
1 cm = 10 millimeters(mm)
Step 2: Bending the Wood for the Shape, Part 1
Another way of making the wood soft and flexible is by putting it into a bathtub filled with water and let it in there for several hours(e.g. overnight). Since the wood will swim in the bathtub, put some towels on top of the wood, so the wood will sink and be completely under water.
Step 3: Bending the Wood for the Shape, Part 2
For my ukulele I've build a shape holder. It puts pressure on the wood from both the outside and the inside and is hold together with a clamp and some tape(I didn't have a second clamp that was long enough).
The shape holder is made out of two layers of cheap wood. To put pressure onto the whole height of the wood, the layers have to be separate
The layers are hold separate with nuts and bolts.
Step 4: Pieceholder at Work
It's very easy to build: First, you outline the shape onto a think sheet of wood with a pencil or something alike. Then you drill holes on the outside of the form you've just drawn. The holes have to be big enough to stick wood-sticks through it. Now put the wood sticks into it, but none of the must be higher than the bended wood itself.
The wood experiences pressure from the outside. Give it some pressure from the inside to by squeezing another wood stick into it.
Now you can begin working on it
Step 5: Closing the Shape
You most probably have to saw the slat quite precisely to fit in perfectly.
Now glue it in and again put a lot of pressure onto it from all sides. Additionally get a rectangular piece to hold the slat straight up.
During this step you can simultaneously go on to the next step: Adding support
Step 6: Adding Support
Add Balsa wood where possible, as it will give your Uke more stability when you glue on the back side and the front side.
After you're finished you should be able to take it out without it losing its shape.
Step 7: Adding the Front Cover
First spread a lot of glue onto the edge and the support you've just added.
Second lay the front wood on top of it and add as much weight as you can, including some clamps
Step 8: Adding the Neck, Part 1
At first you have to add a supporting block of wood, which will later hold the neck. you have to cut the block very precisely. It must touch both, front cover and back cover, so cut it exactly the height so it will fit in the Uke perfectly.
The block has to be in the middle of the uke, right where you want to place the neck
Step 9: Making the Neck Itself, Without Pictures
Step 10: Adding the Neck, Part 2
After the hole is drilled through the block, you have to drill another hole into the neck, but this time it has to be smaller, so that the screw can claw to the wood. Spread some glue onto the area between ukulele and neck.
Finally insert the screw and tighten it, so that the screw can pull the neck firmly to the body.
Step 11: Making the Fretboard, Part 1, and Adding Support Again
But first you have to do some more things.
To make the fretboard you have to glue a long flat wood slat on the front side of the neck, from top all the way down to the prospective soundhole.
Again, clamp it together again until the glue is dry.
While this is in progress, add some support again on the bottom for the cover later.
After you're finished, make a simple bridge and a simple nut and stick on the nut, but not yet the bridge.
The second picture shows the almost finished Ukulele, so don't be surprised when yours does not yet look like this one here.
Step 12: Making the Fretboard, Part 2
Take the distance from fret 0 to the body and note that distance. To know where to put the bridge, go down the same length from the end of the body. Now glue the bridge onto the body.
For the distance between each fret you have to consider two things:
First, the distance from bridge to the end of the body is equal to the distance from the end of the body to the nut.
Second, the distance between each fret has to be calculated, you can either go the hard way and derive a formula given by the facts on wikipedia (http://en.wikipedia.org/wiki/Equal_temperament) like I did... or you make things easy by using this website: http://liutaiomottola.com/formulae/fret.htm
Now sketch the lines of distances and saw along them, deep and wide enough for the frets you're going to put in later.
Step 13: Making Bridge and Nut
The bridge is a little bit more complicated. It is a rectangular stick, with a gap in it, 4 holes for the strings and a cut on the front side for the 14th fret.
Step 14: Adding Soundhole and Bottom Cover
Although you see the soundhole and the bottom cover on the picture, don't glue on the bottom cover yet.
First make the soundhole, somewhere on the uke like shown on the picture.
After you've cut in the soundhole, stick on the bottom cover.
The only thing wood work that has to be done now is sanding the bottom cover, so that it has no protruding parts anymore.
Step 15: You're Finished With It :-D
Yaay, you're done with the wood work. You can be very proud on yourself now.
Now you can color it the way you want, paint a landscape onto it, make it a spider-man ukulele, use your imagination.
After you're done painting, put in the frets, the machine heads and the strings and you can start impressing people by playing on your self-made uke.