Muttley, Light - Scale length.

[32-20-Blues]

Some guy on another forum was wondering why the fret placement on his Epiphone was very slightly different to the fret placement on his Gibson, despite the fact that they both had the same scale length.

Bill Lawrence - yeah, the Bill Lawrence - posted this:

This has nothing to do with USA versus Korean, inches or millimeters, but it's based on a common mistake created by Luthiers with poor mathematical skills.

Instead of using the 12th root of 2 (2 ^ 1/12 = 1.05946309436) to calculate the fret spacing, they used the rule of 18 which is not quite correct (dividing the scale length by 18 to place the 1st fret and then repeating and repeating the same process to place the rest of the frets).

If they would have used 17.81715375 instead of 18,then a 24.750" scale would have been 24.750". Now take 17.81715375 ÷ 18 x 24.750 = 24.4985864 which is about 1/4" short of 24.750".

During my time while at Gibson, I corrected the specs. (Contrary to Gibson, Fender always used the correct calculations.) When Gibson started to make reissues of some Epiphone models, they forgot to change the specs, resulting in a shorter scale.

Bill Lawrence

Had you guys heard about this before? Seems like a stupid mistake...

 

[Roguetitan]

well all I can say is Bill Lawerence knows what he is talking about.

 

[apl]

LOL! That's hilarious!

 

[Light]

Gibson has extensively used three different 24.75 scale length, and used about 1,000 others on just a few guitars. Plus, their fret slotting has not always been all that accurate, but essentially, what Bill said is correct.


Light

"Cowards can never be moral."
M.K. Gandhi

 

[muttley600]

He is right, but when you factor in intonation it all goes pair shaped again..

I do what he does that way there are no compound errors to deal with.

I've mentioned exactly this in the past. If anyone would like to play with the numbers without the hassle of doing the maths, THIS is a very good little bit of software that will show the numbers for all the options.

 

[32-20-Blues]

I'm just amazed that any of us end up playing even remotely in tune.

Thanks for the info, guys.

 

[muttley600]

I'm just amazed that any of us end up playing even remotely in tune.

Thanks for the info, guys.

That all depends what you define as "in tune".

The really tricky bit starts when we want to play in tune with each other..

 

[32-20-Blues]

That all depends what you define as "in tune".

The really tricky bit starts when we want to play in tune with each other..

Ah, don't start with that again....

Life was simpler when I knew less. And that goes for everything - tuning issues, women, whiskey.

 

[muttley600]

Ah, don't start with that again....

Life was simpler when I knew less. And that goes for everything - tuning issues, women, whiskey.