Repairing Improperly Set Bridges:
Tools and Materials:
Plastic Tipped Hammer:
Dremel Moto Tool 4000:
Flat-Cut Router Bit 3/16″ Diameter:
2-Part Epoxy Glue
Woodworkers Marking Knife
Saddle Routing Jig:
Vernier Calipers
Garnet Sandpaper Assortment
In this article we will discuss the repair of a bridge that has been glued in the incorrect position. We could also term this resetting a bridge that has slid out of position due to heat exposure.
I will admit it. This is an extremely rare repair, but I have seen it. For a factory to improperly set a guitar bridge or a luthier to do the same exhibits some real quality control issues and if you find this you are very likely to find some other boo-boo’s that were made in the manufacture of the guitar.
Intonation Issues:
Even a slight misplacement or incorrect angle of the saddle can cause major intonation problems which make the guitar hard to tune, keep in tune and sound just a bit ‘sour’ when we play it.
Check The Scale Length:
The easiest way to check the proper saddle length is to compute the correct scale length. To do this you are depending that the guitar possesses at least a fret scale that was installed correctly.
The scale length of the guitar can be determined by measuring from the back edge of the nut to the center of the 12th fret on the fretboard centerline. This dimension can then be doubled (x 2) and that will be the measurement from the backside of the nut to the center of the saddle, measured on the global centerline of the guitar.
Another way is to just measure to the 12th fret, take that dimension and measure from the centerline of the 12th fret to the global centerline of the saddle.
What To Do With Minor Deviations:
If you find through your measurement investigations that you do have a deviation in this dimension, you do have to make a correction.
If the variation is a 1 or 2 mm, you can usually easily keep the bridge glued in place if it exhibits no other problems.
Fill In The Existing Saddle Channel:
To move the saddle a slight distance, you will need to fill in the existing saddle channel. Do this by following these simple steps.
Step One: Find a scrap of wood that matched the grain and coloration of the existing bridge and carefully thickness it to fight snugly within the saddle slot.
Step Two: Cut the wood filler to length and round the ends so you can get an invisible repair. Also make sure that the existing saddle channel has a flat bottom. If it does not you will have to run a Dremel Moto Tool in the slot to make it consistent.
Step Three: Fashion the channel filler to be about .5 mm or 1/32″ above the bridge top level.
Step Four: Coat the filler with epoxy glue and shove into the channel. Tap snugly into place with a plastic tipped hammer and let dry overnight.
Step Five: Sand the filler flush with the bridge surface.
Step Six: Carefully measure the correct saddle placement and mark it clearly with a Woodworkers Marking Knife.
Step Seven: Take a Dremel Moto Tool with a 3/32″ square cut bit (so it will cut a flat-bottom channel with vertical sides) and cut the proper saddle channel.
Step Eight: Check the depth to make sure it is proper (about 50% of the bridge depth or more). Insert the saddle and string it up.
Ultimate Guitar Repair Tip: Cutting the saddle channel can be a very challenging task. If you have a Saddle Channel Routing Jig, you can make this joint with confidence and get it right every time. I will be publishing plans on how to make one of these useful jigs. They just clamp around the bridge, you se the angle, location and width of cut and set the depth on the router base. One or two passes and your are done!
Tags: bridge repairs, guitar intonation problems, guitar saddle, repairing improperly set bridges
