Thursday, July 26, 2012

Making a Cigar Box Guitar – Part 3

OK, let’s finish off our Cigar Box Guitar.

If you haven’t already read parts one and two, they can be found here: and here:

I want to add some fret markers to the neck, but before that I want to fill in a few holes, as can be seen here:
I glue in some toothpicks:
Cut them and sand them down:
It’s not a perfect colour match, but I think it gives it some personality.

Now for marking the frets, I use an online calculator to determine the positions and mark them out with a pencil. There are many sites that provide fret calculators, but I used the one here and it worked great:

I should add here that since this will be a slide guitar only, we won't need any proper frets, just markers.
Then I use a soldering iron to burn in the lines and the dots:
We pretty much have a complete Cigar Box Guitar at this stage, but I’d like to add some sort of pickup, so I grab a spare piezo buzzer I have lying around from repairing one of my kids’ toys a while ago. I also have plenty of pots and jacks, etc., lying around from doing stomp boxes. Here are the main ingredients:
First, let’s cut a section out of one of the reinforcement blocks to make room for the jack:
And drill a hole for it to pass through:
Then figure out where to put the pot. At first I wanted to put it close to the back end of the guitar top, but this wouldn’t work, as it would be banging into the jack when we try to close the box, so instead it’s moved forwards a bit.

Original position:
Moved forwards:
Hole drilled:
Now we fit the pot and scrape the back of it so that it’s easy to melt a blob of solder onto the back of it.

Blob of solder melted onto it:
Piezo and jack connected up:
Piezos are very sensitive, acoustically speaking, so we need to add some padding around ours so that it doesn’t pick up too much unwanted noise. To achieve this, two pieces of very thin wood are cut out and smothered with white glue and the piezo is sandwiched in-between them, making sure there's room for the wires and the solder blobs.

Making little grooves for the wires/solder:
Adding the glue:
Making the sandwich. Mmmm… sandwich.
Note that the wood I used above was FAR TOO THICK and I had to go back and repeat this step with a much, much thinner solution.

All right, finally (for the electronics), the pickup sandwich is glued into place. Make sure you glue it somewhere that is not going to interfere with closing the box (e.g. don’t glue it in the middle only to find that you haven’t accounted for the neck).
We’re now ready to put this whole thing together, so we glue the wooden reinforcements that we made in the last post into the box:
And then the neck itself is glued in:
Finally we add some screws to each corner of the box. This will seal it closed, but still allow us to open later should the need arise:

Making pilot holes for the screws:
Adding the screws:
Add some strings:
And here’s the finished product:

Sunday, July 15, 2012

Making a Cigar Box Guitar – Part 2

Well the sun’s out again, so let’s get back to work on our cigar box guitar (part one is here:

The next step is to shape the peghead. If we just kept this the same height as the rest of the neck, the strings wouldn’t have any downward pull after passing over the nut and would likely jump about all over it, or buzz, etc. Another consideration is how long the tuner shafts are. Besides, the neck is just too thick for the tuners to reach all the way through anyway.

The neck is currently about 25 mm thick, so I’ve elected to take 10 mm off the top, leaving us with a thickness of 15 mm.

First I mark the depth I’m going to cut off:
Then I do the main cutting very carefully with a wood saw.
And then I add a taper near the nut.
It turns out pretty nicely if you’re careful, and only requires a bit of sanding to smooth things out.
Next, we’re going to deal with the tuners. Firstly we mark where the strings will be if they continue in a straight line from the nut (I'm going for a string spacing of about 11 mm here. This is a bit wider than a standard guitar, which would be about 7 mm.) It’s in our best interests to keep things as straight as possible, although some deviation from straight isn’t the end of the world.
Note that these lines indicate where the outer diameter of the tuner shaft should go, not its centre, since the string will go around the shaft. The holes are marked with a hole gauge, although you can use anything you like, including drawing freehand.
Next, the holes are drilled. You may notice that I have clamped the peghead down on top of a "sacrificial" piece of wood. This is a smart idea if you don't want the peghead wood to split/splint as the drill bit exits.
The tuners are test fitted and the screw holes are also drilled. As you can see, I'm using a very high-tech depth gauge device so that I don't drill all the way through the peghead by accident.
As it happens, one of the tuner buttons is uncomfortably close to the edge of the peghead, so we’ll reshape the peghead a little to accommodate it.
That’s better:
Now we need to shape the neck a little (I remove the tuners again before doing so). There are many tools you can use for this. Personally I’d have liked to use a spoke shave, but I couldn’t find one here, so I’ve ended up using this little one-handed plane. It’s surprisingly effective if you set up the blade just right.
After this, a bit of work with sandpaper smooths things out:
And then a little work with a file to really shape the transition from the peghead to the neck
Now that the neck’s done, I’ll take this opportunity to glue in the ferrules and attach the tuners again.
Back to the body of the guitar (which is to say, the cigar box), we really need to reinforce where the neck and body join, so a couple of supports are made out of some soft wood I have lying around.
Test fitting the neck:
I found these drain covers in a hardware store here for NT$10 each (about 20 pence or 30 cents each), and thought they might work well as soundhole covers.
First I cut out some holes:
Then glue the covers in place:
A quick and easy bridge is fabricated (not that there was much actual fabrication) out of a nut and bolt:
Now we need to figure out how we’re going to anchor the strings at the tail end of the guitar. The following method is recommended in David Sutton’s book, so I see no reason to argue.

First, the end of the guitar is shortened and reshaped a little bit, although neither of these steps are strictly necessary.
Then three holes are drilled, which are thick enough to let the strings pass through, but thin enough to block the balls at the ends of the strings. I think 2.5-3mm is about right for these, but do double-check your own strings.
Then six grommets are located (three for the front, three for the back). These ones came courtesy of my sister-in-law, who uses them for clothing:
Some holes are drilled front and back. Deep enough for the whole grommet to fit, but not all the way through the wood (as you can see from the photo above, I'm using my highly sophisticated depth gauge method again), as otherwise the whole string would be able to pass through, including the ball end.
OK, as you can see, it’s getting dark again, so we’re going to call it a day and try to finish this up (including adding a piezo pickup) in part three (coming soon).