Ibanez Art Series guitar requiring some attention including a replacement nut.
Checking it over: Using calipers and a gauge, the nut distance to 1st fret is 0.5mm greater than it should be. 1st fret will always be sharp irrespective of any other factors. First job will be to fix the nut.
Using a small square file with a safe edge, a small rectangular undercut was made - 4mm high and 0.5mm into the end of the board, flush with the bottom of the nut slot.
The lip was then removed with a standard flat file and safe edge. The 2-file method worked well and kept a good check on the progress and that the amount removed was consistent across the nut slot. (photo shows a small amount of the lip to go).
Time to make a new nut: The bone nut blank was cut and sanded to fit the new slot.
The Nut Replacement Jig is designed for shaping a new top nut, setting out the string spacing and filing the nut action with precision. The jig references the instrument by comparing the nut slot depth with the fretboard crown.
After making the comparison, the jig plates are locked together. This creates a datum reference on the jig identical to the guitars nut slot depth.
The nut is placed in the jig and clamped using the template. The choice of template will depend on the radius of the fretboard.
The purpose of the nut top profile template is to provide an accurate reference for shaping the nut so as to leave a minimal amount of material for nut filing.
The arc of the top profile gradually increases in height from treble to bass. This will leave approx 0.5mm (0.020”) stock material for nut filing at the treble side, and 1.0mm (0.040”) at the bass side.
The nut is placed back on the instrument and the outer string positions marked.
The Top Profile Template is then replaced by the String Action Template.
Note - the top face of the nut profile can be seen with the increase in height from 0.5mm at the treble to 1.0mm at the bass.
The proportional string spacing guide is adjusted left or right until the required string spacing is found (the outer string positions on the nut each align with a guide slot).
The string positions are marked across the top of the nut. The system ensures precise positioning and avoids discrepancies with individual hand marking out of each slot.
(Where the string slots need to be angled towards each individual tuner, a small notch can be made at each string position and the nut placed back on the instrument to determine the angle of each slot).
The slots are finished to depth on the jig with gauged nut files to ensure the string sits in a circular groove.
Because the jig has been referenced directly from the instrument, the top profile of the plate will set the action at approximately 0.5mm over the 1st fret (assuming a nominal 1mm fret height). This is a general guide and will be subject to other factors including the fret heights and string gauges.
Note the original pencil line and relationship to string slots. When the instrument has been strung to tension the slots can be fine tuned as required.
The nut can also be fine tuned in the jig with occasional reference to the instrument. An offcut of the same string gauge will also assist this and help to identify any string binding. (Example photo from 8-string guitar).