A professional guitar tech uses many tools—some common, others highly specialized. This is one of the biggest expenses associated with diving into guitar repair.

Guitar Setups
A pro setup consists of a series of adjustments to make an instrument play its best for your customer. There are five key elements to a setup:

• Adjusting the truss rod.
• Adjusting the action at the bridge.
• Adjusting the action at the string nut.
• Adjusting the pickups on electric guitars and basses.
• Adjusting the intonation.

This is the order for setting up a guitar correctly. If you make these adjustments in the wrong order, you’ll probably have to start over—and perhaps even replace some components.

If you decide to open up a repair shop, you don’t need a huge space. But a mastery of organization and workflow is crucial for success.

A guitarist’s playing style determines how you adjust the above elements. We all play differently and not all guitars are designed to play the same. To assess our customers’ needs, we have to ask them many questions; their answers help us optimize each setup. Here are some of the questions to ask:

• What tuning do you play in?
• What gauge strings do you use?
• What style of music do you play?
• Do you use picks or fingers? What size pick? Fingernails or fingertips?
• Do you use a capo? What kind and how far up the fretboard?
• How do you strum?
• Do you play lead, rhythm, or both?
• Do you use a slide?
• How would you describe your touch?
• Do you control the humidity and temperature where you keep your instrument?

The more you know about an individual’s playing style, the easier it is to set up or repair the guitar to match it. And it’s worth the extra effort: Once you’ve mastered bespoke setups, your customers are likely to bring you more guitars to work on.

Whether you deal with the public or tour with a band, you need to be personable. No one wants to hand over their beloved instrument
to a grouch.

Excellent fretwork demands quality tools, steady hands, and attention to detail. Much like professional musicians rely on ear training, we guitar techs rely on “eye training.” Every aspect of refretting a neck requires training your eyes to recognize fine details. A mistake of as little as 1/1000" can sour a great refret.

The first step is to identify any defects in the fretboard. I recommend evaluating the guitar both with and without string tension. Look for inconsistencies along the fretboard, such as:

• Excessive forward bow with the truss rod tightened.
• Excessive backward bow with the truss rod loose.
• A twisted fretboard with the truss rod both tight and loose.
• Separation between the fretboard and neck, especially near the string nut.
• Kick-up at the end of the fretboard, which is typically caused by the pickguard, exposure to extreme temperatures or humidity, an incorrect shim, or a manufacturing defect.

An excellent refret always begins with a true fretboard. When the fretboard is sanded correctly, it will be straight and consistent, and its radius will be accurate. If you skip this stage of the process, chances are the frets will be inconsistent.

If you know how to expertly refret a guitar and make it play like butter, you’ll soon have a loyal customer base.

Installing the new frets correctly will also save time and materials. Always measure the tang and barbs on the new and old frets to avoid forcing a backward bow or installing loose frets. Whether you press or hammer in the frets, make sure they’re seated flush to the ’board. Watch for any part of the fret popping up, either at the ends or in the middle. This will happen if the fret slots are not cut deep enough or if the tang on the new frets is too narrow. Consider sealing in the frets with ultra-thin super glue, especially if the guitar will be exposed to fluctuations in temperature and humidity.

Dressing the frets is the final stage of a refret. This is where eye training is critical: The goal is to remove the least amount of fretwire while making the frets smooth, polished, and perfectly level. Here’s the process:

• Bevel the fret ends to keep them tight and flush to the end of the fretboard or binding.
• Round and corner the fret ends to eliminate any sharp edges.
• Level the frets to each other by sanding or filing them to prevent any high or low spots.
• Recrown the frets with a special file to create a very narrow point of contact between the top of the fretwire and the strings.
• Scrape the fretboard to remove any excess glue and tool marks in the wood.
• Polish the frets to remove any tool marks and make them shine.

One of the most common tasks a guitar tech will be expected to execute: correctly shaping string slots in the nut to control the height of open strings and avoid binding and buzzing.

The goal is to have frets that feel smooth and provide accurate intonation with no string rattle or dead spots. For a detailed description of fret dressing, read “Squeezing More Life Out of Worn Frets.”

Guitar Electronics
Wiring guitars is an essential guitar-tech service. To qualify as a pro, you must:

Understand how all types of pickups work, including under-saddle piezos, passive and active magnetic single-coils and humbuckers, soundboard transducers, and onboard microphone systems.
Know the color codes for each brand of pickup and how to handle 2-, 3-, and 4-lead harnesses.
Learn various wiring configurations for magnetic single-coil and humbucker pickups, such as coil-tap, reverse wind/reverse polarity (RWRP), in/out of phase, and series/parallel.
• Anticipate potential problems when mixing different brands of pickups, and know how to solve them.
• Be able to identify output jacks—mono, stereo, switching, and TRS.
• Know how switches work—toggle, blade, push/pull, push/push, rotary, and slide.
• Understand potentiometer types and the appropriate values for volume and tone controls.
• Know capacitor types, values, and applications.
• Have professional soldering skills and the ability to neatly organize and secure wires to prevent them from being damaged or interfering with other components.

Tip: Never blow on a hot solder joint. It’s always tempting to speed up the cooling process, but the moisture in your breath can enter the joint and cause it to fail. For more details on soldering, read “Tips for Replacing a Strat-Style 5-Way Switch” and “Soldering 101: A Step-by-Step Guide.”