How can I lower a plastic acoustic guitar saddle?

Question

I got an acoustic steel-string guitar, the nut's height is perfect. Now I want to lower my saddle. It's made of plastic – a bone synthetic for making sure – which I think it's a bit hard to get it lowered down. Well, I've tried to lower it down, but it didn't get lowered as I though it will.

My current action is about 0,5cm, so I assume lowering it down by 1-1.5mm to get 0,4cm action without losing the intonation and getting the fret buzz would work. How can I do that on my own (by not taking it to repair shop) in fastest way?

Answer 1

Normally the bottom of the saddle would be sanded down to lower it. The challenge is sanding it down evenly and squarely. The technique I've seen for this is to fix or hold down the sandpaper on a flat surface and run the bottom of the saddle back and forth over it.

You might consider buying an extra saddle or two and working on a spare so you can keep your guitar in operation while you work on it.

Answer 2

Before you start sanding your saddle down, it is important to be sure you have the truss rod adjusted optimally for your playing style. Excess relief in the truss rod will make the action higher, particularly from about the 4th fret to the fret closest to the sound hole. You might be able to attain a lower action by adjusting the truss rod to flatten out the neck a little more.

You want to confirm proper adjustment of the truss rod first, because adjustments to the truss rod are reversible (if you get fret buzz you can turn adjustment nut the opposite way until the buzz is gone). If adjusting your truss rod yourself, you must be careful not to overtighten and damage either the truss rod and/or the neck and you must be careful to use the correct truss rod wrench and insert it fully to avoid stripping the inside of the adjustment nut. The only way to reverse excess sanding of the saddle is by adding a shim - but adding a shim will compromise the tone transfer from the saddle to the sound board and is not a desirable solution.

To flatten the neck out (take out excess relief or bow) you need to tighten the truss rod by turning it clockwise. This will compensate for the string tension that works to make the neck bow.

After you have adjusted the truss rod, if you still want the action lower, you can sand down the saddle by placing sandpaper flat on a piece of glass and moving the underside of the saddle back and fourth across the sandpaper using a sawing motion. The glass will create a perfectly flat surface. It is important to keep the underside of the saddle uniform and even so that the saddle will maintain even contact with the soundboard.

You don't have to remove the strings completely to remove the saddle. You can just loosen them a great deal and leave the strings wrapped around the tuning posts and remove the bridge pins. Leaving the strings in place makes it easier to reinstall the saddle to check your progress after only a little bit of sanding. Periodically re-installing the saddle, re-tuning the guitar and checking your progress, will help avoid over doing it. It is tedious and time consuming, but not nearly as much as starting over with a new saddle after you discover you have sanded the existing saddle too much.

It is a good idea to have a spare saddle that matches the one you are starting with, in case you do in fact go too far with the sanding.

Even a pro can take too much off if they are not careful. Just take it slow and sand a little at a time. Also, after you have finished sanding the saddle, you might need to tweak the truss rod a tad as well.

Good luck.

Answer 3

10-15 mm seems well too high! With sandpaper, it'll take days/weeks! If it IS that much, then put some paper round it, trap it in a vice, and file it down, with strokes along its long edge, underneath. I hope you meant 1.0-1.5 mm!. Even so, the same approach will work, but bear in mind that once you go too far, the solution is to start again with another saddle, or pack it underneath with strips of paper or a bit off another saddle.

At the same time, if it's not a compensated bridge, you could try chamfering where the second string goes, so that its fulcrum is slightly farther away from the nut than the others.

Answer 4

As a tool nut I'd advise any novice against putting the saddle in a vice to file it down as the normal tendency is to add pressure to the beginning of the file stroke and thus ending up taking too much off one side. Also no mention is made of which type of file to be used but not just any file will work effectively. To be safe a smooth cut (the grade of coarseness) single cut (direction of file teeth rows) file would be the best as it will take off the least amount of stock. The best action would be holding the saddle by hand and moving it longitudinally across (in line with) the file, against the cutting teeth in the same direction each time; no back and forth motion. It is preferable NOT to to shim the saddle if you remove too much, so take your time the first time.