Arlington Fret Works
Guitar Repair
Arlington, VA
ph: 703 969 6233
gojolly2
•Bone saddle & NUT
- Making a bone saddle and nut
Bone Saddle:
The intonation was sharp on this Patrick Eggle acoustic/electric guitar.
The intonation at the saddle can only be adjusted within it's 1/8th inch thickness, so some intonation problems can only be fixed by either moving the bridge, making a new bridge, or moving the saddle slot. Rather than ship it back to England for those warranty repairs the owner decided we should do the best we could with a new saddle.
There were two adjustments I could make. The original saddle was crowned in the middle, and slightly loose, so it tilted forward towards the neck. Because the intonation was sharp I needed to move the string contact points back. The new saddle should be crowned at the back and also be a little bit tighter so it wouldn't tilt. Not too tight because in an acoustic/electric the saddle has to be able to move in the slot in order to transfer sound to the pickup. The string height was fine, so we decided I should match the height of the old saddle and shim.
First I picked the blank with best color and thickness match.
Using sandpaper on a flat piece of marble I sanded the blank flat, and close to the final thickness.
There were two adjustments I could make. The original saddle was crowned in the middle, and slightly loose, so it tilted forward towards the neck. Because the intonation was sharp I needed to move the string contact points back. The new saddle should be crowned at the back and also be a little bit tighter so it wouldn't tilt. Not too tight because in an acoustic/electric the saddle has to be able to move in the slot in order to transfer sound to the pickup. The string height was fine, so we decided I should match the height of the old saddle and shim.
First I picked the blank with best color and thickness match.
Using sandpaper on a flat piece of marble I sanded the blank flat, and close to the final thickness.
Ready for shaping. I cut it to rough length with a hack-saw, then sand close to final size with the belt sander.
Final shaping of the crown with a radius block, to match the fretboard:
I marked the flat top with pencil so I could see where the crown was developing as filed. When this was right I polished the top with 600 grit and up to 4000 micro-mesh. Then I sanded the bottom flat and square, down to the final height.
Finished. Not a typical compensated saddle, but right for this guitar. The intonation is still not perfect, but improved enough to save shipping it to England and back.
Bone Nut:
A customer brought in a nice guitar that he'd made from a kit. I did a few final touches, including making a new nut.
I sized the blank on flat sandpaper to it's final thickness. To mark the top shape I use a pencil that has been sanded in half. With the pencil resting on the first two frets I can trace the level and radius of the frets.
The initial shaping is done on the belt sander, just shy of the pencil lines.
This is a graduated ruler designed for marking the string slots. The thicker strings have to be slightly farther apart than the thinner ones so the spaces between them will be equal.
This piece of bone had some color variations which the customer liked.
I sized the blank on flat sandpaper to it's final thickness. To mark the top shape I use a pencil that has been sanded in half. With the pencil resting on the first two frets I can trace the level and radius of the frets.
The initial shaping is done on the belt sander, just shy of the pencil lines.
This is a graduated ruler designed for marking the string slots. The thicker strings have to be slightly farther apart than the thinner ones so the spaces between them will be equal.
This piece of bone had some color variations which the customer liked.
I make the initial cuts with a very thin file, right on the pencil lines. It's important that the string slots are sloped down toward the tuning pegs. This is critical for intonation. The high point on each slot needs to be at the very front edge of the nut.
With the nut in place and strings on and tuned to pitch I file each slot to it's final depth and width. I have two sets of nut files to cover different string gauges. I like to tilt the file about half way between the plane of the fret board and the plane of the peg head. This gives full bearing of the string as it crosses the nut.
After final shaping and polishing I glue it in with two small drops of Elmers white glue. This holds well enough but not so tight that the nut can't be removed later. The outer strings hold it in alignment while the glue dries.
With the nut in place and strings on and tuned to pitch I file each slot to it's final depth and width. I have two sets of nut files to cover different string gauges. I like to tilt the file about half way between the plane of the fret board and the plane of the peg head. This gives full bearing of the string as it crosses the nut.
After final shaping and polishing I glue it in with two small drops of Elmers white glue. This holds well enough but not so tight that the nut can't be removed later. The outer strings hold it in alignment while the glue dries.
Arlington, VA
ph: 703 969 6233
gojolly2
