Tuesday, March 06, 2007

making a cigar box guitar part 2 - the neck

This a brief description of how I make the necks. I use hardwood like oak or mahogany usually recovered from old furniture and ripped down to approx 20 x 30 mm section and about a metre long. I round off the corners slightly with a plane and rasp then sand down smooth.

I use another guitar neck to find the positions for nut, bridge and frets. I have made a template on thin MDF and use this to mark the positions in pencil allowing sufficient length for the headstock and for the neck to pass through the length of the cigar box and protrude about 50mm for attaching the ball end of the strings.

I mostly use 3 in a line tuners which means you need to remove some material from the front of the headstock to create an angle for the strings to drop down to over the nut (look at a Fender for the principle). I mark the positions of each tuner post and drill three holes for them to pass through.

I place the neck over the box so that the bridge will be about 1/3 up the length of the box and mark the neck about 10 mm inside where the box ends will be. This section which will be hidden in the box needs about 3mm removing - this is to stop the neck resting on the inside of the lid and dulling the sound.

I cut a small groove across the neck where the nut is to go and glue in a large threaded bolt for the actual nut.

I drill three small holes near the bottom end of the neck abou 10 mm apart for strings to pass through. The fret positions and dot markers are now burnt on using a woodburning tool (or old soldering iron). Also my signature "smojo" on the headstock. I "treat" the neck with a couple of thin coats of tung oil then rub smooth when dry with a cotton rag. Finally I attach the tuners.

This is just a rough guide, if you want any tips feel free to leave a comment or e-mail me.

Next part 3 - preparing the box


Pete said...

Hi Smojo Man! I'm visiting your site for tips as I'm about to make two biscuit tin instruments (steel strung ukulele and a two string bass!) for a show.
I noticed your method for finding fret positions - have you heard of the "rule of eighteen"? In a nutshell you reduce the string length by 1/18th for each fret. You can then have any scale length you like. Pete.

David said...

Pete - first thanks for visiting my site and leaving your comment. No I haven't heard that rule, I'll check it out. I have been taking the easy route and copying the scale off a guitar but that's pretty useful to know. Smojo

Steve said...

Hi. The exact spacing between frets is one divided by the twelfth root of two. Using a scientific calculator type in "2", and then press the "log10" or simply "log" button (actually some calculators now make you type in the "log" button before the 2, but that's bye the bye). Divide the result by 12, then press the "10x" button, which is often the same one as the log button but you have to press an up arrow key or somesuch. You'll get an answer close to 1.06. Divide "1" by what you've got, and you get the exact ratio between frets. You can then multiply whatever string scale you choose by that ratio. After 12 multiplications you'll find you end up with half your original string length, which is the octave.

David said...

Steve many thanks for that.

Susan Graham said...

It’s a pretty interesting tool. I will definitely be using it once I get the chance. Thanks for sharing!

Lord Glencoe said...

Hi Smojo Man, viewing your page, it's good & interesting, plenty of tips on building. I noticed the comments on fret placement, all too difficult for me. I use a free program you can download from the web, it's called Wfret. You can choose the scale length, the number of frets required & then print out a template of the fret marks to transfer to the neck. I call it idiot proof, that's why I use it, check it out, Bazza

David said...

thanks Bazza - In true cigar box guitar building style, I'm still using my MDF template with felt tip pen marks on it that I copied from an old Teisco electric. Seems close enough for my purposes