String Slot Spacing for 7 String Guitar

[mrblue]

Hello,

I'm looking for suggestions on how to space the string slots, in a nut, for a 7 string guitar, so that the space between each string is equal. I have a string spacing ruler from StewMac, but that doesn't seem to work for 7-string guitars.

Thanks!

 

[StringPluckery]

Do you have calipers to measure and mark the slots?

 

[Omzig]

take off the fret board overhang (space from the center of the Low B and High E to the edge of the nut i use 5mm ) then divide the remaining length into 6 equal parts

or use

https://www.ekips.org/tools/guitar/fretfind2d/

if you want to be lazy

 

[Winspear]

Usual is ~4mm overhang on the edges so with a 48mm nut for example that's 40/6=6.66mm center spacing

 

[mrblue]

Hello,

Thanks for all your input. Much appreciated.

However, based on what I've read, if you simply take the center-to-center string spacing between the low B and high E, then divide by 6, the spaces between each string will not be equal. This is because the diameter of each string is not being taken into account. So that would mean, the space between the 7th and 6th strings would be smaller than the space between the 2nd and 1st strings.

Does anyone know of a formula for calculating the string spacing, accounting for the diameter of each string so that the space between each string would be equal?

Thanks.

 

[ixlramp]

Yeah, i was wondering which spacing method you meant, i know of 3:
1. String centre to string centre being equal.
2. String edge to string edge being equal (Perhaps the most common?).
3. String centre to string edge being equal (Makes sense thinking of a finger centred on one string but needing to clear the adjacent lower string).

 

[dmlinger]

4mm is a bit too much in my experience. Most common is 1/8th inch (3mm).

 

[Omzig]

what gauge strings are you using? ungoldly 125 gauge or something?

I just tested this out in a CAD layout and you are taking about 0.4-0.6 of a mm on lower string and 0.05 on the high E & B strings, do you really think it will have much of an effect on feel of the guitar with the string width accounted for ? i think your making work for yourself TBH.

 

[ixlramp]

It is worth using edge-to-edge to optimise and maximise the space between strings, especially since it is very little extra mathematical work and no extra cost.
Half a mm is a significant distance.

@mrblue here is what i am thinking (you should check this yourself):

Start with nut width.
Subtract both string-edge-to-fretboard-edge distances.
Subtract the total width of all slots.
Divide by 6.
Result is string-edge-to-string-edge distance.

Then use various combinations of these distances to obtain the positions of each slot.

 

[ElRay]

... very little extra mathematical work ...

Agreed, assuming you're using parallel frets. If you have a multi-scale design, the ratio of center-to-center distances at the nut and the bridge have to be the same.

 

[MaxOfMetal]

Hello,

Thanks for all your input. Much appreciated.

However, based on what I've read, if you simply take the center-to-center string spacing between the low B and high E, then divide by 6, the spaces between each string will not be equal. This is because the diameter of each string is not being taken into account. So that would mean, the space between the 7th and 6th strings would be smaller than the space between the 2nd and 1st strings.

Does anyone know of a formula for calculating the string spacing, accounting for the diameter of each string so that the space between each string would be equal?

Thanks.

Go to the link for Fret Find that @Omzig posted and choose the "proportional" option for string spacing. It's exactly what you're looking for.