Fretboard Radius Explained
Neck Radius: What do the numbers mean?
The fretboard radius is a commonly misunderstood term, incorrectly referred to “neck radius”, which leads people to think about the wrong part of the neck. The radius only pertains to the curve of the fretboard, which dictates how the guitar will play and feel just as much as the neck profile. A common Fender radius like 9.5” refers to the arc of a circle with a distance of 9.5” from the center to the outer edge. You can do this right now by taking a pencil attached to a string (cut to a 7¼”, 9 ½” or 12” length). Tack the loose end of the string to a surface and draw a perfect circle. Now, if you were to cut out a segment of the circle approximately 2 inches wide, that’s the exact curve of the fretboard! With the geometry out of the way, take a look at these types of curves and imagine what would happen when you bend an outer string upwards, especially up high on the neck.
Image Credit GretCat
In general, the string is more likely to “fret out” as it approaches the arc in the middle of the fingerboard. With 7 ¼” radius necks, a common remedy is to raise the action of the outer strings, or at least the B and high E.
Guitars are only as versatile as the player but the radius can help point you in the right direction. For strumming chords and riffs, lower radius fretboards have always been a popular choice. Many players love a smaller, rounder radius for rhythm playing because it comfortably matches the curve of your hand, especially for bar chords. A 50’s Telecaster is a good example of a guitar that’s ideal for “cowboy chords” because of its very round 7 ¼” radius (along with its twangy tone of course!) That’s not to say there aren’t plenty of blues legends pulling majors bends of a 50’s Tele. Setting the correct saddle height is very important on this type of guitar. Let’s thank Leo for designing a bridge with height adjustable saddles because a tune-o-matic style with this radius would compromise your playing. That being said, a flatter 12” radius Les Paul can manage with their predetermined saddle arc two adjustment posts.
An easy saying regarding radius is, flatter=faster. When the strings are at an even height, you can move your fingers faster across them and also perform bends efficiently without less fretting out. ESP, Dean, and Jackson all have a flat fretboard radius from 12-16”, obviously aimed at those who like to rip it up!
Other Bending Factors
Radius alone isn’t the only aspect that affects playability. Fret size plays a major role and perhaps deserves a segment of its own. There is a reason you see larger frets on fast, modern, guitars. I remember playing a friend’s Richenbacker and I could hardly play a solo since the action was so low and the frets, almost gone. But it was probably one of the easiest guitars for bar chords all the way up the neck! The point being, it’s the sum of the parts when talking about playability.
I think this is a brilliant “best of both worlds” approach at providing you with the rounder radius for chords and a flatter radius up high on the neck for bends. You can find aftermarket compound radius necks from places like Warmouth, who generally offer 10-16” compound. A conical radius actually offers a gradual change from a smaller rounder radius to a flatter one. Parker guitar are one example of a 10-13” conical fretboard shape.
Image Credit Guitar Answers
Now that you understand what the curve on top of the neck does for playability and feel, let’s dive into the shape of the neck, or profile. Fender started using a letter that closely resembled the actual shape of the neck. The famous Nocaster has a large U shape that is not for the small handed! It has a chunky feel that gives a guitar a feeling of sturdiness and sustain. Due to its high shoulders, some players might not be able stretch across the board the same way as with a shallow profile. “V shape” necks allow for your hand to stretch over the fretboard easily and come in hard or soft shapes. This profile is favored by those who like to use their thumb over the top of the fretboard because the absence of a rounded shoulder makes the neck fit snuggly in your palm. However, the sharp angle of the “hard V” results in an edge that runs down the center of the neck which may be uncomfortable for some players A good compromise that Fender came up with was the oval “C” shape, like on the 62’ Strat. It doesn’t have the depth of the “U” or the extreme angles of the “V”. You’ll find a shape like this on most other guitars because it satisfies the majority.
Besides Fender’s system, there are all kinds of standards from different manufacturers. Ibanez’s Wizard is extremely flat and fast (17mm and the first fret, 20mm at the 12th). Skinny necks are good for beginners and professional alike however some players say that not enough support from the neck profile can cramp their hands. You can often find a diagram complete with measurements on the product’s website but if the numbers don’t tell you much, the best way to find out is to try it in your own hand. Just like a pair of shoes, a neck that doesn’t match your hands can lead to fatigue after long periods of playing.
A guitar’s mass, whether it may be from the body or hardware plays a large role in its ability to sustain notes. By that logic, neck thickness must have some sort of affect on the sustain as well. However, it is more about the sum of the parts rather than one specific point. For me, there is some mind over matter involved. Just knowing that a neck is fat will convince me that the guitar has better sustain and a fatter sound. I can’t prove or disprove it, I just like it! So, that’s what it really boils down to, if it feels comfortable and it allows you to play without impeding your skills, you’ve found your neck profile. So next time you grab a guitar, take note of the curve of the fretboard and the feel of the neck but most importantly, let your hands decide.
See you next time in the corner,