If the fingerboard is the backbone of your guitar, then your guitar’s neck is all the supporting structure that keeps it aligned. Although your guitar’s neck provides some contributions to your guitar’s overall tone and appearance, your main concerns should be strength and comfort.
Your Guitar’s Neck Contour and Heel
The contours of the rear of the neck should be the first point of inspection when considering a guitar purchase, because they are designed purely for the player’s comfort. Although the carve of a handcrafted guitar yields necks that are unique to that instrument, there are several typical contours that describe the thickness and curvature. “Fat C” and “Shallow C” refer to C-shaped cross sections of varying thickness. U and V shaped contours are also available and an “Asymetrical V” provides the maximum thickness of the curve closer to the bass strings instead of centered on the neck. My only advice is to try guitars and necks with different contours and choose the one that is most comfortable to your hand and finger size.
Set neck vs. Bolt-on neck vs. neck-through
If you read the any marketing literature from the major guitar manufacturers, there are various reasons for each of these types of neck construction to give you the perfect tone. The truth is that they are all perfect methods of attaching the neck to the body as long as it is attached properly. The neck/body joint on the guitar is the most obvious link in the guitar where you want a rock-solid connection. This connection may be accomplished by a good glue joint, 4 wood screws, bolts, or by building the neck as an extension of the body. If the joint is tight, you won’t lose any sustain and your guitar will resonate properly. When buying a guitar, just ensure that the joint is tight and that the neck lines up with the bridge, horizontally and vertically. From an ease of construction standpoint, the bolt-on neck is a simple joint, followed by the set neck and neck-through construction, so expect that prices will follow the effort that your builder puts into them.
A general rule of thumb is that hard, dense wood will provide a brighter tone that less dense wood. However, keeping in mind that slabs cut from the same log will provide a different tonal response, the main purpose of the neck is to support the fingerboard and resist the pulling forces of the strings. To accomplish this, the neck must be carved from a strong hardwood, typically mahogany or maple though other hardwoods and exotic woods can be used. A truss rod, embedded within the neck will also counteract the string forces, so as long as the neck is constructed of hardwood, treat this as a cosmetic item.
When the strings break over the nut, toward the tuners on the headstock, a downward angle anchors the strings to a single point at the front of the nut to provide accurate tuning and keeps the strings from vibrating within the nut. This downward angle can be created by angling the headstock back, by placing string tees on the headstock to pull the strings lower, or by utilizing tuning posts that decrease in height further from the nut. All of these methods yield the same results, so choose what you’re attracted to. Pay special attention to the area where the neck transitions to the headstock. Since this is the thinnest part of the neck, within the area that is bearing the force of the strings, any cracks or loose glue joints will grow worse over time unless repaired properly.
An example of neck construction with an angled headstock is shown in the video below:
Truss rod types and access
As mentioned earlier, the neck should contain a truss rod to counteract the force of the strings on the neck. The truss rod may be a static section of square rod, a single adjustable rod, or a double adjustable system. I recommend an adjustable rod, since weather and seasons will cause wood to shrink or swell, causing the neck to flex more or less. When these changes happen, the adjustable truss rod allows you put the neck back in alignment. A single adjustable rod allows adjustment to counteract the force of the strings, where most neck movement occurs. A double adjustable rod can bend the neck forward and back, in the rare chance that seasonal neck movement overcomes the force of the strings and must be adjusted forward. Truss rod access is typically at the headstock, behind the nut, or at the body end of the neck, via a pickup cavity. Beware of body-end adjustment nuts where no access point is available via the pickup cavity. You should not need to access it frequently, but you won’t want to remove the neck of your guitar to access a truss rod nut.
In the next installment, I’ll discuss the upper components of your guitar that hold the strings: the headstock and nut.