Home Making a New Fingerboard Hospital


Making a new fingerboard

This often becomes necessary if the old board disintegrates too badly during removal; or you use the old board as shim; or as sometimes happens, the old board is a poor replacement, does not fit the scale length, the frets are badly spaced, or it has lost part of fret 1 to make it fit the scale length better. (or any permutation of these!!)

   The first task when building a new board, is to work out the fret positions. DO NOT try and cut the slots excatly as the old ones were, it is very possible they are not accurate, and it is unlikely that you can 'transfer' them accurately enough assuming they are well placed. The best way to go, is to start from scratch.

   Scale Length: you must first decide what scale length you want. (Distance between nut and bridge) Leave enough room for a bridge itself to fit before the cant, plus 2-3mm in front of it for adjustment. (To achieve accurate tuning, the bridge often needs to be a little over the theoretical scale length.) Then, this point to nut....... is your scale length. The bridge should NEVER be behind the cant line.

   Fret Positions: the positions of the frets is worked out using a mathematical formula. 

  • The magic number is 1.059463 for 'twelve tones of equal temperament in a perfect octave'. 

  • If you divide the scale length by this number, it will give you the theoretical distance from the bridge to fret 1.

  • Now divide this figure by 1.059463, to give you the theoretical distance from the bridge to fret 2.

  • Now divide this figure by 1.059463, to give you the theoretical distance from the bridge to fret 3.

  • Proceed like this until you have all the 17 or 22 frets calculated.

   Now, it is difficult to measure fret positions from a point not fixed on the instrument, (the bridge...) it makes more sense to measure from a fixed point.... the nut. So.....

  • Deduct the distance from bridge to fret 1 from the scale length, and you have the distance from the nut to fret 1.

  • Deduct the distance from bridge to fret 2 from the scale length, and you have the distance from the nut to fret 2.

  • Continue with these deductions until you have distances from the nut to all the fret positions.

  • Measurements are then ALL made from the nut (end of the fingerboard or zero fret...) to the given fret position, NOT from fret to fret (too easy to make cumulative errors!).

   Example: Try this one and see if you agree with the figures, if yes, then you have it correctly.

  • For a scale length of 336mm divide by 1.059463

  • Fret 1 will be 317.14199mm from the bridge

  • Fret 2 will be 299.34201mm from the bridge

  • Fret 1 will then be 336 - 317.14179 = 18.85821mm from the nut

  • Fret 2 will then be 336 - 299.34201 = 36.65799mm from the nut

Start with a piece of ebony or rosewood, a little wider and longer than necessary, and about 4mm thick. Draw a centre line, and line up with f/b jig centre-line.

Clamp wood onto the jig. I often use double-sided tape beneath as well.

Clamp the metal ruler to the blank f/b so that there are no accidental movements.


From the end of the board, or the zero fret, measure the position of each fret very carefully, and mark with a knife/scalpel on the centre-line.

After removing the rule, score with a knife right across the board. I use a set square along the straight edge of the jig, to keep these lines perpendicular to the centre-line.

Once scored, I use a fine Japanese draw saw to cut each line, again using the set square to keep the cut perpendicular.

Take great care not to cut too deeply, if in doubt, put a piece of masking tape along the saw edge about 2mm from the bottom of the teeth as a guide.

Using the same technique, I then widen the cut with a fret-slot saw with adjustable height guide.

Having placed the finger board on the neck, carefully line up the centre-line with the centre-line of the mandolin. Pencil where the edges of the are underneath, and mark where the sound-hole end should be cut.

Plane down the sides to just outside the mark, and cut the sound hole end.

   I usually fit the MOP position markers at this point. They are variously at frets 3, 5, 7, 10, and 12, but occasionally on concert models at 15 as well.

   Frets can be fitted before or after the fitting of the f/board as required. I often do it afterwards which gives you a chance to level the f/b once glued before you add frets. Alternatively frets can be added first, especially if the f/b is extended across the sound hole, but they will undoubtedly need levelling afterwards.