How to Determine the Bridge Placement on a Guitar

The center of the saddle needs to line up with the center of the fingerboard.

Placing the bridge correctly on a guitar is important if you want your home-made guitar to play in tune. The guitar’s bridge is the section which holds the strings to the body and also contains the saddle, which holds the strings up to the desired level. In reality, the position of the saddle is the most important thing, because it determines the vibrating length (or scale length) of the strings, thus affecting the guitar’s intonation. The bridge should always be twice as far away from the nut as the 12th fret and central to the fingerboard.

Things You'll Need

• Ruler
• Pencil
• Masking tape

Instructions

1. Measure the distance from the inner edge of the nut to the middle of the 12th fret marker. Locate the nut by looking up to the top end of the guitar’s neck, which can be identified by the larger frets. The nut is the small piece of white material which separates the guitar’s neck from the headstock. Find the 12th fret marker by counting down the first 12 metallic strips from the nut, or alternatively looking for the fret marked with two pearl dots. This is the 12th fret, and the metallic fret marker on the opposite side from the nut is the 12th fret marker.

2. Double your measurement to find the correct position of the saddle in relation to the nut. Write this figure down in case you need it later. For example, if your guitar is the same size as a Gibson Les Paul, your measurement to the 12th fret will be 12 and 3/8 inches, which would double to give you the full scale length of 24 and 3/4 inches. Measure this distance from the nut and make a small mark on the guitar’s body at this point with your pencil. The bridge will cover this, so don’t worry about marking your guitar’s body.

3. Measure the bridge from one end to the other. Bridges will be wider than they are long, so measure the width and make a small mark at the half way point on the underside of the bridge. This will give you an idea of the central part of your bridge. This should also be the center of the saddle. The saddle is the thin, usually raised rectangle which supports the strings. The key factor is for this to be aligned perfectly with the nut. Ensure your mark is made at the center of the saddle. If you have an irregularly shaped bridge, just measure to determine the center point of the saddle.

4. Mark the bridge on the front side at the center point with a bit of masking tape. Use two bits of tape to form a small arrow that meets at the center point to make a precise mark.

5. Locate the center point of the fingerboard. You can measure the fingerboard at the body side, and make a masking tape mark at the center point. Line the center point of this up with the center of the saddle. Use a ruler to ensure that these are in line. Ensure the saddle sits directly over the mark you made after your measurements from the nut. You can measure the same distance from the inside of the nut that you wrote down earlier if you want to be sure your bridge is correctly placed.

References

• Stew Mac: Scale Length Explained
• 12 Fret: Guitar Scale Lengths
• Lutherie Information Website; Locating an Gluing the Bridge of a Steel String Guitar; Liutaio Mottola; June 2009