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Stew Mac Gibson fret scale
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Author:  dzsmith [ Wed Feb 06, 2019 4:44 pm ]
Post subject:  Stew Mac Gibson fret scale

I’ve been using the Stew Mac Gibson fret scale for laying out the fret locations.
I noticed on their website they state the positions were derived by measuring many guitars.
I belive Gibson used the rule of 18 for the fret locations instead of the more exact 17.82 number.
I’m wondering if the intonation is off on the scale?
Any insight?

Author:  Chris Pile [ Wed Feb 06, 2019 6:39 pm ]
Post subject:  Re: Stew Mac Gibson fret scale

17.82 is commonly referred to as the rule of 18....

And Gibson has a bunch of scale lengths, the most common of which is 24.75 (or thereabouts).

Author:  Freeman [ Wed Feb 06, 2019 6:45 pm ]
Post subject:  Re: Stew Mac Gibson fret scale

There was an article in AL a few years ago about the three main changes in Gibson's 24-3/4 scale. I'll see if I can find it.

Author:  dzsmith [ Wed Feb 06, 2019 9:39 pm ]
Post subject:  Re: Stew Mac Gibson fret scale

Chris Pile wrote:
17.82 is commonly referred to as the rule of 18....

And Gibson has a bunch of scale lengths, the most common of which is 24.75 (or thereabouts).


I believe Gibson used the literal 18 to derive the fret locations?
24.75 / 18 = first fret slot.

Author:  dzsmith [ Wed Feb 06, 2019 9:42 pm ]
Post subject:  Re: Stew Mac Gibson fret scale

Freeman wrote:
There was an article in AL a few years ago about the three main changes in Gibson's 24-3/4 scale. I'll see if I can find it.

Don’t go to too much trouble Freeman,
I doubt my marking and cutting is very precise.
Just wondering if the scale is based on antique or modern calculations.
Dan

Author:  Andy Birko [ Wed Feb 06, 2019 10:49 pm ]
Post subject:  Re: Stew Mac Gibson fret scale

Chris Pile wrote:
17.82 is commonly referred to as the rule of 18....


That's not quite true from what I understand. 17.82 is the more ideal number which is the 12th root of two. 18 is a close approximation to the more ideal 17.82 but they are distinctly different beasts.

Rule of 18 fretboards intonate differently than 12th root of 2 fretboards. I have a couple clients that vintage-ise new Gibson LPs to vintage spec and the fretboards I cut for them are slotted to a 24.75" scale calculated using the rule of 18 as opposed to the 12th root of two and the frets definitely don't line up between the two.

Some examples.

1st Fret: 1.389 for 2^1/12 but 1.375 for RO18

12th fret: 12.375 vs. 12.285

21st fret: 17.392 vs 17.298

Definitely different beasts and you can hear the difference.

Author:  B. Howard [ Thu Feb 07, 2019 8:16 am ]
Post subject:  Re: Stew Mac Gibson fret scale

Gibson has used at least 3 different variations of the 24.75" scale... The shortest actually measuring just over 24-9/16" true scale. True scale is double the length from nut to 12th fret. and has no bearing on actual divisions used to obtain scale....

Author:  Ken McKay [ Thu Feb 07, 2019 9:33 am ]
Post subject:  Re: Stew Mac Gibson fret scale

Some frets are going to be sharp or flat no matter what method to place them.

As Andy wrote, there is a different placement at the first (and other) fret with different methods of scaling.




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Author:  Chris Pile [ Thu Feb 07, 2019 12:00 pm ]
Post subject:  Re: Stew Mac Gibson fret scale

Quote:
I believe Gibson used the literal 18 to derive the fret locations


They surely weren't stupid enough to take that literally....

Author:  Andy Birko [ Thu Feb 07, 2019 12:04 pm ]
Post subject:  Re: Stew Mac Gibson fret scale

Chris Pile wrote:
Quote:
I believe Gibson used the literal 18 to derive the fret locations


They surely weren't stupid enough to take that literally....


Yes, they were as well as just about everyone else who didn't have a calculator.

Author:  Freeman [ Thu Feb 07, 2019 12:14 pm ]
Post subject:  Re: Stew Mac Gibson fret scale

dzsmith wrote:
Freeman wrote:
There was an article in AL a few years ago about the three main changes in Gibson's 24-3/4 scale. I'll see if I can find it.

Don’t go to too much trouble Freeman,
I doubt my marking and cutting is very precise.
Just wondering if the scale is based on antique or modern calculations.
Dan


Well I couldn't find the article. As I remember one of the changes was going from 18 as the divisor to 17.8xxxxx (whatever the 12th root of 2 is) but there was another change and I don't remember why they did that.

While I was digging in old issues I did run across three or four different articles talking about better fret locations to help deal with string stiffness and all those other little frustrations. Next time I build an electric I may move some frets and compensate the nut...

Author:  Ken McKay [ Fri Feb 08, 2019 2:08 pm ]
Post subject:  Re: Stew Mac Gibson fret scale

Guitars are frustrating if you don't just pick a method and stick with it.


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Author:  John Lewis [ Wed May 22, 2019 1:31 am ]
Post subject:  Re: Stew Mac Gibson fret scale

https://www.youtube.com/watch?v=0yCLckbp8ps

This is a great explanation of scale length - Martin vs. Gibson.

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