Neck Specs For Left Hand Ease— Guitar Care 101

tonebase Guitar
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6 min readSep 9, 2018

In his sixth installment of Guitar Care 101, luthier Gary Lee discusses the importance of playing an instrument whose neck fits your hand’s personal anatomy. Using diagrams and detailed pictures, Gary demonstrates the minor differences that can make one neck drastically more comfortable than another. If you missed it, make sure to check out his last GC101 post — “Tuning Machines: What’s New (and Old)” — here!

What Neck Features Determine Left Hand Comfort?

Next to it’s sound, the way your guitar feels in your left hand will determine if you are going to have a long and happy relationship together.

But what is it about some guitars that make them feel so comfortable and others not?

Second to action — which we addressed in Blog 4the key to left hand comfort is having the correct neck shape followed by width and thickness. These variables are set during construction, so if a guitar purchase is in your future, it’s helpful to know what factors to pay attention to.

Let’s start with the take home message, and get to the details later

If you are considering buying a guitar that’s already built…

…pay particular attention to how the shape and size of the neck influences the comfort of your left hand. Apply the same level of scrutiny to the feel as you do to the sound. Both the feel of the neck and the sound are generally locked in at the time of construction and cannot be undone. Are you equally happy with both? If the answer is “no,” it may not be the guitar for you.

If you are having a luthier build you a guitar…

…have an in-depth discussion with your luthier about the types of neck and fingerboard shapes/sizes that you have liked and disliked in the past, and how those compare to what the builder proposes to build for you.

Before I build a client’s new guitar, if I cannot work with the player in person, I will sometimes ask him or her to send tracings of the cross-sectional shape of their favorite neck. As shown below, a contour guide purchased at a hardware store can be used to get an imprint of the back of the neck.

Even if a new guitar is not in your immediate future…

…keep mental notes of the necks you’ve liked or disliked (and why) when you try your friends’ guitars or those at stores and festivals. What is it about the shape and size of their necks that made them a joy or a pain? This awareness will be valuable to you when the time comes for your next instrument.

Now for the details!

Small Differences Are Meaningful

Your hands are incredible. They are so sensitive that they can feel differences in shape and size that you’ll never see. It’s not surprising that your hands can have a preference for differences as small as 0.4 mm.

It’s not necessary that you see what is or is not comfortable to you. Trust your extraordinary sense of feel to decide what’s too much, too little or just right. Unless the fit is close to perfect, it could feel like you are fighting a piece of raw lumber.

The Top 5 Factors for Left Hand Comfort

(In order of importance…)

1. Neck Shape

By neck shape, we are more specifically referring to cross-sectional shape. The diagrams below show three basic shapes.

Like everything else in guitars, personal preference guides what is best for each player. Having watched hundreds of guitarists’ left hands while listening to their comments about comfort, the area on the neck that lies behind the 4th and 5th strings is one of the most influential regions for left hand comfort.

As shown in the photo below, the reasons are two-fold: 1) in this location, the thumb and fingers have the least amount of gripping strength, and 2) it’s where the back of the neck starts to rapidly curve toward the fingerboard.

To some players, a small hump in this region can feel like an abrupt cliff. As a consequence, many players prefer it flat or rounded here, while others prefer it to be the thickest spot on the neck’s cross section instead of directly in the middle. The bottom line is if the thumb doesn’t sit comfortably in this crucial region, the player will suffer from a lack of efficiency.

2. Fingerboard Width

A fingerboard’s width, in conjunction with the string spacing, sets the difficulty of vertical stretches. While decreased width makes vertical stretches easier, the decreased string spacing makes finger placement more cramped, requiring greater accuracy. Fingerboard width on most contemporary guitars ranges from 52–53 mm at the nut and widening to 62–63 mm at the 12th fret.

3. Neck Thickness

Similar to cross-sectional shape, the thickness of a neck strongly influences left hand ergonomics. While intuitively it may seem that thinner is better, for the technique and anatomy of each player, there is an optimal thickness that maximizes left hand efficiency. Thicknesses typically range from 21.5–23 mm at the 1st fret to 22.5–24 mm at the 8th fret.

4. Fingerboard Relief

Relief refers to the slight, upward curvature of the fingerboard. As we will discuss in the next blog installment, a little is helpful, while too much can make your left hand feel as if it is drowning in quick sand.

Comparison of 640 mm to 650 mm scale length

5. Scale Length

Many players assume that scale length is at the top of the list for determining left hand comfort. For most experienced players playing contemporary guitars, however, that’s usually not the case.

Look at positions of the fret slots on a 650 mm scale fingerboard compared to those on a 640 mm scale fingerboard. Since half of the 10 mm difference falls between the 12th fret and nut, the reality is that only 5 mm of the difference is spread among the first 12 frets.

Unless you are playing a 660 mm or larger guitar, scale length is a relatively minor factor.

That’s all for this installment, and oh no! Only one more Guitar Care 101 post left! Make sure you’re all caught up on Gary’s other posts before the last on Fingerboard Relief. You can find all the installments as well as many other articles on all things guitar by visiting our Medium homepage here. And of course, find more great classical guitar material over at!

About Garret Lee —

Garrett Lee has enjoyed playing guitar since the age of nine. In 1999, his fascination and curiosity with guitar design, coupled with his love for woodcraft, drew him to begin building classical guitars. Trained as a research scientist with a Ph.D. in biochemistry, he enjoyed a successful career in academic research and later, in biotechnology. He was compelled by the challenge and intrigue of lutherie to transition to full-time building in 2006.

Gary’s research background inspires creativity, thoughtful design, and exacting execution. His handcrafted classical guitars incorporate traditional and contemporary design. Midway through his development, Gary received mentorship from celebrated American luthier John Gilbert.

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