Guitar Neck Scale Length?

The scale length is the distance between the nut and the bridge. The Les Pauls and similar guitars have a scale length of 24 3/4 inches. The Strats and Teles have a scale length of 25 1/2. These are the most used scale lengths because the LP, Strats and Teles are the most used guitars but there are much more possibilities.

The basses have a scale length of 34" (Precision, Jazz) but some models also have a shorter scale length (30"). And some manufacturers use a larger scale length for the 5 strings basses (Lakland, 35").

A couple of links with more information:

https://www.guitarnoise.com/lessons/scale-length-explained/

http://www.12fret.com/fret/fv4n7.htm

It has to do with the strings themselves.

Vibrating strings produce a specific pitch related to the length, tension, and mass of the string. You need the tension of the strings to be roughly the same (otherwise uneven tension could twist the neck over time). If you've got strings under the same tension, the heavier strings will produce lower tones... pretty obvious, just from looking at a guitar.

If you make the strings longer, each string will have to be under more tension to produce the same pitch. That puts an effective upper limit on scale length - probably at about 27" or so - where you'd have to have strings thinner than we can produce; if the strings got any longer they would snap under the tension. Going the other way, guitars have to be longer than about 22", otherwise there's not enough tension... the strings tend to slap against the fretboard at times, which is why guitarists playing very short scale length guitars often tune higher than standard.

So we've got to make guitars in roughly a 5" span dictated by physics and the limits of our string making capabilities. The rest is pretty much history - the dimensions of the "standard" guitar dates to the 1850s, and a builder named Torres. He set the length at 650mm, about 25.6 inches. If you already play a guitar, you'll be most comfortable playing one with the frets in about the same places... so builders tend to bunch up right around this measurement: Fender at 25.5, Martin at 25.4, etc. (Torres wasn't the first to use 650mm, but he was probably the first to use it exclusively - before that, scale lengths varied a lot)

Gibsons are a bit shorter, ranging from around 24.25 to 24.75 depending on the model and year. I'm not sure why that's the case - although Gibson was among the first to make guitars with metal strings, they were using shorter scale lengths for at least 10 years before that development. It might be because Gibson started by making mandolins, and they had a longer scale length than standard for that instrument; as a result some folks criticized early Gibson instruments as being hard to play... they may have decided to make guitars shorter than standard to avoid similar criticism.

At any rate, most makers follow either Fender (Torres?) at about 25-1/2, or Gibson at about an inch less. And most players tend to like one or the other. Shorter lengths make it easier to bend strings, because there's less tension; longer lengths make it easier to change instruments - I use 25.5" electrics because I use 25.4" acoustics and 650mm classicals; all the frets are within a fraction of an inch of the same place from one instrument to the next.