Dumbest brainfart question.. Mix and match scales..

For guitars of the straight waisted variety (or reverse offset).
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tribi9
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Dumbest brainfart question.. Mix and match scales..

Post by tribi9 » Sun Dec 20, 2020 9:14 pm

This would work right?

A 25" 1/2 neck on a 24" body, tuned to E#, with a capo on the first fret.

It would intonate and be tuned to standard, right? :ph34r: :jacked:

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Re: Dumbest brainfart question.. Mix and match scales..

Post by sookwinder » Sun Dec 20, 2020 10:14 pm

the tuning has no effect on whether it would intonate correctly.
The distance from the nut to the bridge RELATIVE to the fret spacings will determine correct intonation.

So a 25" neck (with fret spacing for a 25" neck) that is needing a body that adds the additional correct distance to the bridge can only work if that body is set up for a 25" neck. If you fit the 25" neck to a body that is designed for a 24" inch neck the intonation will be screwed
relaxing alternative to doing actual work ...

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Re: Dumbest brainfart question.. Mix and match scales..

Post by timtam » Mon Dec 21, 2020 1:21 am

One of the curious things about 24" and 25.5" necks (but not other arbitrary scale pairings) is that the fret locations for 1st->last on the 24" neck are the same as fret locations from 2nd->last on a 25.5" neck. You can verify that by checking the fret to fret distances with any online fret position calculator, or with a ruler if you have both scale guitars. So a 25.5" scale neck is just a 24" scale neck with an extra fret added at the headstock end of the neck.

On the 25.5" neck, the distance from the 12th fret to the bridge is of course 25.5"/2 = 12.75". But the distance from the 13th fret to the bridge is 12". So if you capo at the first fret on the 25.5" neck, you effectively have a new nut location (at the first fret), and you effectively move all fret numbers up by 1. So the bridge on the 24" scale body is in the "right" position for a 24" scale, now measured from the 13th fret of the 25.5" neck (and you have one less fret at the end of the neck). A capo at any fret on any neck has the same scale-length changing effect, just not perfectly in the increment necessary for a 25.5"->24" scale change.

EDIT: The problem with this is not with the fret geometry theory above, but with actually attaching the 25.5" neck to the 24" body. While you could build a 24" body (or a 25.5" neck) where the placement of the 25.5" neck in the 24" neck pocket resulted in a distance of 12" from the 13th fret to the bridge, that won't be the case when pairing typical 24" bodies to 25.5" necks.
Last edited by timtam on Mon Dec 21, 2020 4:22 pm, edited 1 time in total.

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Re: Dumbest brainfart question.. Mix and match scales..

Post by SignoftheDragon » Mon Dec 21, 2020 9:40 am

...and your fret markers would all be one space off.

Theoretically it should work, but would the intonation really stay true all the way up the neck?

Try it, and post results!

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Re: Dumbest brainfart question.. Mix and match scales..

Post by countertext » Mon Dec 21, 2020 10:04 am

I think it’s more complicated than that...

The distance from the base of the neck pocket to the bridge is different, and I don’t think it’s exactly the same as the first-fret distance. I think the relationship of the bridge to the fret spacing is more out of whack than can be fixed by just capoing at the first fret.

Or maybe I should say, if it intonates with a capo at the first fret, it will intonate with a capo at any fret or with no capo at all, and then necks could have been swapped all along... which we know isn’t true.

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Re: Dumbest brainfart question.. Mix and match scales..

Post by tribi9 » Mon Dec 21, 2020 12:21 pm

SignoftheDragon wrote:
Mon Dec 21, 2020 9:40 am


Try it, and post results!
Cant, i have a 24" body but i dont have a neck that fits the pocket unfortunately.

:(

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Re: Dumbest brainfart question.. Mix and match scales..

Post by timtam » Mon Dec 21, 2020 4:17 pm

countertext wrote:
Mon Dec 21, 2020 10:04 am
I think it’s more complicated than that...

The distance from the base of the neck pocket to the bridge is different, and I don’t think it’s exactly the same as the first-fret distance. I think the relationship of the bridge to the fret spacing is more out of whack than can be fixed by just capoing at the first fret.

Or maybe I should say, if it intonates with a capo at the first fret, it will intonate with a capo at any fret or with no capo at all, and then necks could have been swapped all along... which we know isn’t true.
On reflection I think you're right. If the distance from the 13th fret on the 25.5" scale neck to the end of the pocket when attached to the 24" body was the same as with a 24" neck, then it would work (because then the distance from the 13th fret to the bridge would really be 12"). But that's unlikely to be the case - you would have to build a custom body or neck to exploit the unique relationship between the fret geometries of 25.5" and 24" scales. The unique fact that the fret spacings are equal on 24" and 25.5" - just one fret offset - led me to forget about that other consideration. I have edited my earlier post to correct that.

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Re: Dumbest brainfart question.. Mix and match scales..

Post by tribi9 » Mon Dec 21, 2020 5:17 pm

Right, the neck pocket location.. I knew it was a silly question..

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