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Fun With Fretboards by Bob Smakula 

Posted by permission. Originally printed in the WINTER ‘95 edition of THE OLD-TlME HERALD 

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It has been said that mandolin players spend half their time tuning and the other half playing out of tune. Last fall I discovered the reason for this, and now I give those mandolin players slack.

Two old Gibson A-model mandolins were in my shop at the same time. One of them had a fretboard that needed replacing; the other had worn frets and needed re-fretting. Old Gibson A-models have thicker fretboard s than those we commonly find on instruments built today, so I cut up some ebony and sent five fretboard blanks out to Duke of Pearl ( custom fret slotting transfered to Allen Guitars mid "96) , who sell Mother of pearl and other shell inlay products and do custom fret slot cutting. The custom fret slot cutting is something I can do myself but A. G. has jigs that can do the job faster and more accurately than I can in my shop.

Two weeks later my mandolin fretboards came back from California. Anxious to get the fretboard replacement project rolling I opened the box and checked the fret slot spacing against the 1927 Gibson A-model that was in for refretting. I could not believe my eyes. When I lined up the end of the new fretboard With the nut on the old Gibson the only fret that was dead on was the 12th fret. What was wrong?

I was not about to spend ten or more hours on a fret board replacement without assuring myself that the new fretboards would work perfectly. I sliced a small section off a new fretboard, glued it to a bigger block of wood, put frets in, installed a tuner, and set up a nut and bridge. Then I strung it with a mandolin E string and clipped on a Piezo transducer to create a one string solid body mandolin. I plugged the transducer into my strobe tuner, set the bridge so it was in tune at the octave (the 12thfret)and prepared myself for the worst. The plan was to use my strobe tuner to check intonation accuracy. With a strobe tuner you can check how many-cents, (1 /100 of a semitone) flat or sharp a note is. I was sure that A. G. had ruined my fretboards. 

With my E string in tune I went to work. First fret-F-perfect. Second fret-F# perfect. Third fret-G-perfect. By now my keen sense of the obvious had noticed a trend. Yes indeed, all the fret slots cut by D.O.P. / Allen Guitars were perfect. It was time to test out the 1927 A-model. I put on a fresh E string and set the bridge to be in tune at the 12th fret. First fret-flat 5 cents, second fret-flat 8 cents, third fret flat 13 cents, fourth fret-flat 10 cents, fifth fret-flat 8 cents. From the fifth fret to the twelfth fret the fret placement gradually sharpened until it was perfect at the twelfth fret.

After that bit of disappointing news, I checked three or four other Gibson mandolins that were in my shop with similar results. The age range of the Gibson mandolins I tested ranged from 1909 to 1939, and their frets were in the wrong position. I assume that current instruments are manufactured to modem standards. The 1927 A model was by far the worst with the 3rd fret going 13 cents flat. The average was 10 cents flat at the 3rd fret. For me, 10 cents flat is too much. Even 5 cents is too far out of tune. A good question is, "Why, after playing old Gibson mandolins for 2O years have I finally noticed this?" I have no idea.

I do know that the corrective action needed to get the mandolin to play perfectly in tune is to replace the fretboard. The first step in removing the old fretboard is to apply heat to soften the hide glue that is holding the fretboard in place. With a little water and a thin spatula to slide into the glue joint, I can usually pop a fretboard off in one piece. Next, with a band saw, I trim the new fretboard to slightly larger than final size. The final fretboard shaping is done with hand planes and sanding sticks. To prevent the fretboard from slipping when I glue it on, I drill two small holes through three fret slots into the mandolin. Small nails are used as locating pins. Once the glue is dry, the nails are easily removed, and the tiny hole is hidden by a fret. The actual gluing of the fretboard is another quite tricky job. The only flat surface for a clamp to squeeze on is the fretboard itself. To prevent the clamps from crushing the wood on the neck and back of the mandolin, I have an arsenal of clamping cauls that fit irregular surfaces on one side and are flat on the other for good clamping contact.

A few days after the glue has dried I level the fretboard and inlay mother of pearl position markers. When the glue holding the dots dries, I sand off the excess glue and polish the fretboard with progressively finer grits of sandpaper. New frets are next. That process includes tapping in the frets with a hammer, leveling the frets, then re-crowning and polishing the frets.

Now I am ready to install the nut, string up the mandolin, and be the envy of all the mandolin players on my block. This process is quite time consuming. I charge $350 for an unbound fretboard and $450 for a bound fretboard. With that kind of money involved you really have to think twice before having the work done. Another aspect to think about on old vintage instruments is their collectability. A rare vintage mandolin might be worth more "as is" than in tune.

If your mandolin needs re-fretting and has the original out-of-tune fretboard, it is a good time to replace the fretboard. The cost of re-fretting is about two-thirds the cost of a new fretboard, and after this work has been done, customers have been enthusiastic-their mandolins sound better and play in tune.

What if fretboard replacement is out of the question. My best recommendation is to move the mandolin bridge so it is in tune in the first position, splitting the difference of the out-of-tuneness between the third and fifth frets. It will make the instrument go sharp at the twelfth fret, but I and most other mandolin players spend most of their time on the first five frets. I’d like to think that mandolin players whose mandolins have fretboards with proper spacing will still spend half of their time tuning, but the other half playing in tune.

update: Along with providing a custom fret slotting service, Allen Guitars also sells exotic woods such as rosewood and ebony fretboards (slotted or un-slotted) and cast mandolin & reso tailpieces.


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