i was inspired by stumbling upon a cigar box guitar. i needed to have one of these in my life and so should you.
i loved making this and its relatively simple.
heres an idea of how i made it

Step 1:

First thing I did was cut the front and back shapes.
Then measured the sides and cut suit.
Are used 3 mm ply for this.
Next I glued all the sides to the back leaving the front off and left them to dry.
wood glue or gripfill will be suitable

Step 2:

I found the piece of hardwood for the neck from an old door opening. Hardwood is good because it won't bow from the string tension.
Cut it 50 mm wide 30 mm thick and 900 mm long. Leave one end 100 mm² for the headstock.
Cut the 3 mm Length of the top of neck by putting the top of the base on it.

Now offer the neck up to the back side of the box. Mark and cut the front side so It sits down flush. Set it in place and screw the back.

Step 3:

Glue the top on. (Clamp and tape).
Get a hardwood strip the same width as the neck to the length you want and glue also.

Step 4:

All leave it to you to make/find something for the bridge.(bolt thread etc)
I bent a piece of brass and screwed to back to pick up the strings.

Step 5:

Cut out a shape out of back with the jigsaw allowing access for pickup. I got a piezo from eBay for 3 pounds.
Drill a suitable hole inside for the jack and stick the other end on the underside of the bridge.

Step 6:

I have left a few things out but hopefully commonsense will get over them. String up and get plugged in. If all else fails you can always bury your dead pet in it………. Enjoy