HOW TO CONVERT A GUITAR INTO AN OCTAVE-MANDOLIN.NOTE: 7 additional photos and a sound sample of this instrument are available. Click here for information.
Several years ago I was given a fairly inexpensive semi-acoustic electric guitar. Being that I don't play electric guitar, I converted it, in a few hours, into a long-necked, octave mandolin, for the price of two new tuning-machines, strings and some small hardwood scraps. The resultant instrument is wonderfully rich in sound/tone and volume & is a whale of a lot cheaper than ready-made octave mandolins. This conversion is so easily accomplished that it can be described quite quickly and easily. ADDING TWO ADDITIONAL TUNING GEARS ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Elderly Instruments (& many others) sell inexpensive (less than $10 per set) guitar or mandolin tuning machines (aka tuning gears). I simply bought a set, hacksawed them into individual units, drilled the proper mounting holes at the head-end of the of the tuning box (there always seems to be room here to squeeze in another couple of tuners) & slapped em on. My two new tuners jut out at about a 45 degree angle, but this is of no consequence. // _ _ _ _ \\ //\ / \ /\\ <-- the 2 new tuning machines '' \/ \/ '' / O O \ | | ,, | | ,, ||--| O O |--|| '' | | '' | | ,, | | ,, ||--| O O |--|| '' | | '' | | ,, | | ,, ||--| O O |--|| '' \ / '' \ ___________ / ||| || || ||| <-- the new 8 string nut |~~~~~~~~~~~| | | | | NUT ~~~ Remove the existing 6 string nut. Use it's shape as a pattern to whittle/file out a new hardwood nut. Carefully plot out and cut-in the grooves for 8 strings. Make sure the 2 strings nearest the edges of the neck are not TOO close to these edges. It seemed to work out niceley here that each of the strings within the 4 pairs should be about 1/8" apart. If in doubt, initially just make very slight grooves & only deepen them once you're satisfied with the spacing. TAILPIECE ~~~~~~~~~ The electric guitar I used utilized a conventional metal "fasten to the end of the guitar-body" type tailpiece. No conversion was made to it -- I simply (& quite effectively) hooked the ends of the two new strings through the existing string-holes. One was a bit tight with two strings now going thru it, and I probably should have drilled the mounting hole out a bit. BRIDGE ~~~~~~ This guitar had a "set-on" type bridge. I fashioned a new similarily shaped bridge out of rock maple and notched it for the four pairs of strings. This has worked out quite satisfactorily. Such a bridge need not be "streamlined" or fancy. Calculate it so that the grooves in the bridge allow the two outer strings to run down the neck about the same distance from the neck-edge along their lengths. Once again, initially make only very light grooves here & deepen them once you're satisfied with the spacing. WHAT TO DO IF YOUR BRIDGE IS THE "THROUGH THE BODY" TYPE WITH NO TAILPIECE: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Remove the bridge saddle & ether a) add new grooves for 4 string pairs or b) Make a new 8 string saddle out of plexiglass or some other hard material. The two additional strings can be secured through the High E and low E bridge holes (this may necessitate "grooving" the associated mounting pins a bit deeper to take into account the fact that there now are TWO strings going thru each hole). Now just string it up, adjust the action & play it! On the several instruments so converted here, I have had no sign that the additional pressure of two extra strings caused any problems. The former electric guitar, for instance, stays in tune from year to year - hanging most of the time on the wall! I used appropriate gauge individual guitar strings, although they do sell octave-mandolin (or Cittern) strings in several catalogs. Over the years I've converted lots of instruments from one thing into another and must say that this guitar - octave mandolin conversion ranks about the most successful ---- very easy to do too. ................................................................. Late note (August 2002): Derek Darling had this neat idea, although not claiming it to be an original idea: "I took a 12-string guitar and used it for an octave mandolin. 1. Remove the low E and the G string(s) 2. Move the remaining high strings (E and B) over to the next set of spaces. 3. Retune the A string to G, the D string stays the same, the old B string down to A, and the new E (high) string stays the same Viola, now you have an octave mandolin. Another variation is to have all the strings in unison, more of a Bouzouki sound. .................................................................. Dennis Havlena - W8MI Straits of Mackinac northern Michigan Click here to access my home page.