This conversion was initiated as a bit of a whim but the results turned out much 
more impressive than I'd imagined -- well liked by everybody who's seen & played it.

Basically I took a cheap ($5 at a garage sale) steel-stringed, classical-ish
guitar and reworked the nut & bridge, added a couple of guitar tuning-gears
& a banjo 5th string peg, added a simple tail-piece, put on light gauge strings
& ended up with a different but not-bad-looking contraption that nicely serves these 
three purposes (only the tuning & playing style need be changed):

- a quite useable & unique banjo, with each playing string doubled-up (12-string guitar 
  fashion) and a single 5th string

- an very nice sounding/playing "octave mandolin"(aka cittern, bazoukey) 

- a resonant "12-string" --- make that "8-string" tenor guitar.

A word about each:

Banjo: Has a very interesting sound. While not something you'd play all the time it's four, 
double playing stings plus a single 5th string give it a decidedly rich & way different and
pleasing sound. Much fun to play. I only clawhammer, mainly in gCGCD tuning but this thing can 
be just as easily finger-picked (in any banjo tuning). Besides, it's a heck of a conversation piece!

Octave Mandolin: It's very hard to tell the tone and playability from that of a fancy, expensive 
commercial jobbie! Can be easily tuned in conventional GDAE tuning or any variant (CGCE being 
my own favorite tuning). Played with a flat-pick.

Tenor Guitar: With the four double strings, this makes for a rich-sounding tenor guitar - not that
tenor guitars are played all that much nowadays but quite fun none-the-less. Tuned in conventional
DGBE tuning - same as the highest four strings on a guitar. Finger-picked or played with a flat-pick.
CLICK HERE to see a YouTube video of this converted guitar being played

Obviously, adding three strings to a 6 string instrument sounds like a recipe for disaster but 
is really not. Look for and buy the lightest gauge strings possible. sells a wide 
variety of light-gauge banjo strings. Overall, because these light strings replace the heavier 
bass strings on the guitar, the three extra strings are not an issue. Having said that, obviously
don't use an expensive or favorite guitar for this conversion. 

I use these strings: 
.009" plain for the two 1st & the single 5th strings
.014" plain for the two 2nd strings
.023" wound for the two 3rd strings
.032" wound for the two 4th strings

Fancy nut files can be used to cut the additional grooves in the nut but an old hack-saw blade
will work as just as nicely. 

No real commentary on the mechanics of this conversion are really necessary -- just refer to the
photos closely. Not much is critical.

This conversion is quite easily accomplished. It took me less than 2 hours - start to finish.
Dennis Havlena - W8MI
northern Michigan

Click here to access my webpage