Conversion of an electric mini-guitar to Electric Octave Mandolin

Completed Electric Octave Mandolin


Shown is an electric octave mandolin that started it's life as a $99 mini-guitar. Total cost was approximately $200 with the additional cost of items used in the conversion. This process is a fairly simple, and could be done with the information given here if you have some basic woodworking skills and a few basic power tools. A drill press and 4" tabletop belt sander were the primary tools which I used.

Electric Octave Mandolin Specifications:

Additional parts and where they were obtained:

Basic conversion process:

Click on any of the following images for a larger view.

Altering the existing headstock profile:

The existing headstock is carefully layed out, cut, flipped, and reglued to other side to accomodate the new Schaller A-style tuners. This photo should de-mystify the radical reshaping of the headstock. The addition of a thin pre-bent veneer on the face makes this modification almost invisable, with the only real clue of the instrument's original configuration being the filled tuner holes visable on the back side.

Modifying the original bridge for octave mandolin use:

The existing bridge was very easily modified for use as an octave mandolin bridge. The existing saddle adjustment holes for the 2nd and 5th strings were drilled out with a 9/64" drill for the new #6 X 32 X 1-1/2" stainless steel saddle adjusting screws.

The outer string holes were close enough to use them again for the outer-most G and E strings. New 1/8" holes were drilled immediately TOWARD THE CENTER from these holes for the G and E unison strings. The existing 3rd and 4th string holes become the new closest-to-center D and A string holes, with new 1/8" holes drilled immediately to the OUTSIDE of the original holes. Ideally all string pairs should be as close to 3 mm as possible.

The saddles were formed from two 5/16" X 1-1/4"(33mm) pieces of brass rod stock. They were sanded flat on one side to allow drilling a #29 hole through each end to house each set of #8 X 32 X 3/8" allen head saddle height adjustment setscrews. Two holes 7/64" in diameter are then drilled at an approximate 5 degree angle in the center of each saddle's face. These are then tapped for the #6 X 32 X 1-1/2" stainless steel saddle intonation adjustment screws. Round the sharp edges and assemble the bridge using 2 1-1/4" springs over the screws between the bridge plate and saddle.

How does it sound? Any further ideas after playing it awhile?...

It sounds great, I was amazed at the fullness of sound this little instrument produces. I play regular mando already, and plan to add this to some of the tunes that I perform which lend themselves to the fuller tone of this instrument. It's possible short-coming is the scale length is a little long to cross over all the standard mandolin fingerings, but the sound is great... especially when routed through my small tube amp.

A little further down the road, I'll probably opt to make a new pickguard for it and eliminate the pickup closest to the bridge. I'll shift the center pickup 1/2" or so toward the bridge at that time. Also, I'll eliminate the tone control, move the volume control to the existing tone control location, re-locate the pickup selection switch farther toward the bottom of the body and orient it parallel to the strings. I'll also change it to a 3 position Tele-style switch to select front/both/rear pickups. The selection switch needs to be re-located to prevent bumping it if you become a little too wild in your playing. Other than those small details, she's a keeper!

Further information alert...

Watch for a future link to the complete guide and text for the mini-guitar to octave mando conversion hosted off-site.
Bandwidth restraints restrict viewing the entire guide at all times, but the entire step-by-step guide is accessable by using the following link. There's always a catch to free hosting!

Complete guide to Electric Octave Mandolin Construction
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