Eastman AC412 (OM) string spacing for new nut

[Stringbuzz]

I’ll soon be building a new nut and saddle for my Eastman AC412 and could use some advice.
There are a few issues and I’m not sure what to do with the spacing on the new nut.

I really like the extra space on the 1 ¾” neck, but the width and the spacing are new to me. The spacing seems to be neither center to center nor equal spacing, is this normal for an Eastman?

One issue is that on the original nut the treble e is close to the edge while the E on the bass side is further away (string center to edge e=2,55mm; E=3.6mm).
The treble e string sometimes slides off if my hammer-ons or pull-offs are not precise. Maybe my technique just needs improvement, but I’m wondering what other people’s experiences are regarding the minimal distance to the edge before the strings might slip off during play?

Also, would it be better to have a more symmetrical edge spacing on either side?

[JonWint]

Some builders use proportional slot spacing. Can be performed using:

http://www.stewmac.com/Luthier_Tools...cing_Rule.html

It tries to make the clear space between strings equal. You still need to choose outside E,e clearances. If you are pulling e off, add .5mm or more. You can calculate the spaces yourself using actual string diameters if you don't want a new tool.

[mirwa]

An expanding rule has been applied for that nut you show, that is E-B is one size gap, B-G is slightly larger and so forth across the fretboard, your outer string distances look fairly okay as well, they are edge of string to edge of board not centre of string to edge of board, I personally find 3mm edge of string to edge of nut comfortable to play.

Nothing wrong with moving your high E further across to suit your playing style

Setev

[Stringbuzz]

Thanks for the tips guys.
The "expanding rule" seems a good explanation of what's going on.

I use light strings so the edge spacing from edge of string to edge of fingerboard (measured with calipers) would be:
Treble side: 2,55-0.15= 2,4mm
Bass side: 3.6-0.68= 2,92 mm

That's is quite a bit less on the treble side than the 3mm you suggest Setev.
It's funny that looking at the photo the treble side distance seems ok, I don't know why it's a bit slippery there sometimes.

John, I think your idea is good, and if I add 0.5 to the treble side then I'd end up with the same spacing on both sides.
The only downside is that I'd have a 37,5mm E-to-e spacing instead of 38mm.

I wouldn't mind using calipers and doing some calculating, then perhaps I could move the bass 0.5mm towards the edge?
But I do have a very simple spacing ruler which was part of a cheap kit I got and it does have a 37,5mm spacing on it (center to center), check the pic.


I'm probably being too anal about this, losing half a millimeter shouldn't be a big deal right?!