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).


Jim said...

Really enjoying these thanks. Your explanations are clear and well illustrated. Looking forward to the next part!

stu said...

Thanks, Jim!

Gustavo Comanduci said...

Great project! Great finishing!
I am enjoying your blog a lot! Congratulations from Brazil!

Anonymous said...

Really cool! Often using the same sophisticated method for drilling, except mine tape(thanx god i´ve found it!) is yellow. Nice stuff you´re doing anyway, just finished passive mixer today, everything fine. Thanx, keep on groovin´. Mike