How to Set Up a New Mandolin

Many mandolins ship from the factory or even from some small independent builders in need of a good set-up, and if there’s one thing any mandolin requires to live up to its potential, it’s being set up properly.

Setting up your mandolin doesn’t mean framing it for taking the last piece of pie that you know darn well you ate yourself, but includes adjusting the action, intonating by positioning the bridge, and in some cases carrying out fretwork.

If you’re handy with a few tools and measuring devices, you may be able to do some of this basic set-up work yourself. If you’ve never done this type of work but think that you want to give it a try, get some instruction first from a qualified set-up professional. In addition, you can buy instructional DVDs on this topic, and an ever-growing list of YouTube do-it-yourself videos are available to help in this process, too. Most mandolin players can perform the basic set-up tasks of adjusting the bridge, but take the more advanced jobs to a pro.

Even a great guitar technician may do a terrible job on a mandolin set-up. The shorter scale, and the stiffness of the double strings of the mandolin require much more precise tolerances than a guitar.

In this section I cover a few easy jobs that you may want to try yourself with a few basic tools. Stewart-MacDonald and Tonetech are suppliers of specialty tools and parts used in the making and repairing of string instruments. Some of these tools are quite expensive but can make the job much easier. Also, Frank Ford, at Gryphon Stringed Instruments in Palo Alto, California, has a wealth of additional information on set-up and other issues about the care and feeding of a mandolin, available online.

If you’re even a little intimidated or feel uncomfortable at the thought of carrying out the set-up procedures, leave them to the pros and go to your acoustic music specialty shop. Believe me, a good mandolin set-up technician is a great friend to have.

Adjust the Action

Action describes the distance you have to press the strings down to get a fretted note to ring properly. Mandolin strings are very tight when tuned up to pitch, so having the action low makes your mandolin easier to play and causes less pain to your fingertips. However, if the action is too low, the strings buzz and rattle against the frets.

Many mandolins built since the 1920s have adjustable bridges with two thumbwheels that you use to raise or lower the overall height of the bridge. You can adjust these thumbwheels in two ways:

• Loosen the tension on the strings until you can turn the screws with your thumb.
• Use a screwdriver with a wide flat tip inserted near one of the thumbwheels, between the bridge base and the bridge top. Carefully turn the handle until it takes enough pressure off the thumbwheel by lifting the bridge top so that you can adjust the thumbwheel. The following figure demonstrates this method.

Most mandolin players like their action to be about 1.5 millimeter (0.06 of an inch) high at the twelfth fret. You can measure this distance with metal feeler gauges or a rotary depth micrometer. Although a bit pricy, these micrometers take all the guesswork out of the job. Some very experienced luthiers and set-up technicians can set the action by eye, but I prefer to measure it. The next figure shows this measuring tool.

Tackle the Truss-rod Adjustment

Some mandolins have an adjustable steel rod running the length of the neck, called a truss rod. This steel rod is designed so that by turning the nut on the threaded end of the rod, you can adjust the straightness of the neck. A bowed fretboard makes for high action and poor intonation. If your mandolin neck has a bow to it, a truss-rod adjustment (which somehow sounds more unpleasant than it is) may be able to straighten the neck.

The truss rod screw or nut is located in the headstock, under a cover plate. You have to remove a few small screws to access the truss-rod adjustment screw. After you’ve removed the cover, determine what type of tool you need to make the adjustment. Some truss rods require an Allen key (or wrench), and others a thin-walled socket wrench. You can purchase truss-rod adjustment tools from luthier supply stores.

If your mandolin’s neck is bowed forwards, turn the rod to the right. A very small amount can make a big difference, and so only turn this rod about one-eighth of a turn at a time. If the neck is back-bowed or bent backwards, making the strings buzz against the frets, try loosening the truss rod by turning it to the left.

Some modern mandolin builders are putting a two-way adjustable truss rod in the neck. This type of rod pushes or pulls the neck in either direction, thus making this whole process easier. Check out the following figure for a view of the truss-rod adjusting procedure.

Slot the Nut

The action (or string height) at the first fret is very important for getting your mandolin to play easily and in tune. This measurement is overlooked quite often in lower-priced mandolins, but I’ve also seen many expensive mandolins that are very hard to fret because of this problem. If you think that your mandolin is hard to play on the frets nearest the nut, you may want to measure the action at the first fret. I use a rotary depth gauge (as shown in the previous figure) for this job.

I like the action at the first fret to be about 0.3 of a millimeter (0.012 of an inch) for the E-string and about 0.38 of a millimeter (0.015 of an inch) for the G-string, with the A- and D-strings being somewhere in the middle (see the following figure). You can get different-sized metal files made specifically for slotting the nut. Try to find files that are slightly larger than the string you’re slotting. For instance, if your E-string is 0.254 or 0.28 millimeters (0.010 or 0.011 of an inch), look for a file that’s about 0.33 of a millimeter (0.013 of an inch).

Cutting or deepening the nut slots can be a little risky, and so go slowly. One swipe too many with a file and the nut is ruined.

Set the Bridge: Intonation

Mandolin bridges are held in place by the downward pressure of the strings; they aren’t glued down. In order to get the mandolin to play in tune all the way up and down the neck, the bridge must be in the correct location.

The term intonation refers to how well the instrument plays in tune. You can check this aspect by using an electronic digital tuner while moving the bridge very small amounts. Below are step-by-step instructions to set the intonation on your mandolin:

1. Tune the mandolin using an electronic tuner so that all the open (that is, unfretted) strings are in tune.

2. Fret each of the strings at the twelfth fret (the octave) and observe the reading on the tuner:

• If the tuner is reading flat or lower than it should, move the bridge towards the neck a small amount.
• If the tuner is reading sharp or higher than the open string, move the bridge back towards the tailpiece a bit.

A millimeter or two (say, 0.06 of an inch) can make a huge difference, and so be careful not to move the bridge too far. Notice that in this figure, the open string and the twelfth fret are both in tune.

3. Check that the bridge is upright and not leaning one way or the other.

If the bridge is leaning, carefully set it straight.

Sometimes, however, the bridge needs to be at a slight angle to get the best intonation on all the strings. And, sometimes, adjusting a bit for one pair of strings might throw one of the other pairs off, so repeat as necessary to get as close to perfect as you can for all the pairs.

Attempt the more involved set-up procedures that I mention only if you’re confident with your handyman skills. A professional set-up technician has the special tools and experience to carry out these procedures.