Degree of slant to a fan fret

[Doubleneck]

I saw this awesome looking guitar over in the Carbon area and noticed the slant to the fan fret seemed more severe than I think I have seen from other builders. In there a rule of thumb here?

[rogthefrog]

Several considerations come into play:

* the range of tunings you're trying to optimize scale length for (that will dictate the spread between the high E and the low E)
* where you want the bridge to fall relative to the top / bracing
* where you want the bridge to fall relative to the player's fingers, so that you don't get weird tonal differences between the low strings and the high strings when played in a natural position (if the slant is extreme, it's easy to get "ponticello" tone on the high strings in a neutral playing position, which may not be desirable)
* where you want the perpendicular fret to go (player comfort)
* how much stretching is required on the low frets (player comfort and hand size)

Many fanned frets guitars tend to have the perpendicular fret around fret 7 or 8, but I've seen them higher or lower. The spread also varies a lot, from 1/4" to well over 1" in some guitars.

[JamesO]

As rogthefrog mentioned, it's relative to the two scale-lengths. I just finished a guitar with 25 and 25.75 scale-lengths, with the perpendicular fret at fret 9. It's really comfortable and I don't notice the fan at all. Tonally, it's working well for my goals. I play primarily in DADGAD, wanted it to sound defined in Open C, and still wanted to be able to play in standard without worrying about the tension on the top. So far it's great. A few nights ago I actually tuned it down to a Bb version of DADGAD and it was still doing well! That was probably the limit, though.

There isn't a rule, but it was recommended to me to stay close to traditional scale-lengths initially.

[TEK]

That one appears to be close to a 2" difference in scale lengths.

[perttime]

Another consideration is how much your forearm, hand and fingers naturally change angle from vertical when you move them horizontally. People generally move the hand more than the elbow, so the angle changes.