software

hey guys
i was using the stew mac fret scale calculator to find bridge post distance for a tuno matic bridge
and im just curious why, when i enter 22 frets and a scale length of 24.75
the posts of the tuno matic bridge are spposed to be at 24.811quot; (±0.030quot;) from nut to center of treble-side post. Mount bass-side post 1/8quot; further from the nut.

isnt this a bit far for the scale length of 24.75quot;
can you guys explain why this is so?thanks

i will take a shot at this, but one of the luthier guys will have to give you the definitive answer ...

i think of this whole thing as a right triangle ... the 24.75quot; scale length is the long leg ... the bridge is the short leg .... and the line from the nut to the treble side post is the hypotenuse, so naturally it must be the longest measurement

no clue on the bass-seide extra 1/8quot; deal, unless it turns out to be the same situation, only mirror image

hope this helps
t4d

alright
here's the dilly as far as i've always understood it
the reason that the bass side of a tune-0-matic bridge is swept back is becasue of the limited travel of saddles in a tune o matic
since bass sides always are farther from the nut than trebble sides when you intonate (a result of different stringt thicknesses, etc.)
on a tune o matic you sweep the bass side back 1/8 to give the saddles a quot;head startquot;
this effect lesses as the scale length increases
and its why prs and fender guitars dont' require this (typically) even when using tune o matic style bridges

as for why the scale length isn't 24.75 - becasue there are 2 gibson 24.75 scale lengths (as far as i know)
1) 24.75
and 2) one that's a little off and is supposed to be more correct

hope that helps
i don't make 24.75 scale length guitars for this reason - i want to avoid the debate of scale length of which one is the quot;real dealquot;
however, on my 25quot; scale guitars, i do always sweep the bass back 1/8 on a tune o matic

thanks guys
so its safe to use those measurements

That extra length is some built-in compensation. Remember, the distance from the 12th fret to the bridge has to be longer than that from the nut to the 12th fret. This is because fretting the string stretches it, making the note go sharp.

Remember, the quot;scale lengthquot; is a nominal indicator, not a real measurement. You won't really find anything that's 24.75quot; from the nut. What a 24.75quot; scale really indicates is that there is (24.75quot;/2) or 12.375quot; from the nut to the 12th fret.

All strings require some compensation even the high E, so that's what your calculator is showing - a little bit of compensation on the high E, and more on the low E.


Originally Posted by Rich_SThat extra length is some built-in compensation. Remember, the distance from the 12th fret to the bridge has to be longer than that from the nut to the 12th fret. This is because fretting the string stretches it, making the note go sharp.

Remember, the quot;scale lengthquot; is a nominal indicator, not a real measurement. You won't really find anything that's 24.75quot; from the nut. What a 24.75quot; scale really indicates is that there is (24.75quot;/2) or 12.375quot; from the nut to the 12th fret.

All strings require some compensation even the high E, so that's what your calculator is showing - a little bit of compensation on the high E, adn more on the low E.

My experience is that the angle on a tunomatic is unneccessary for a properly tempered intonation scheme provided you do your initial measurements properly. Over the next day or two I'll try and post some photos of guitars I have re-intonated here so you can see what i mean.


Originally Posted by orion_riderhey guys
i was using the stew mac fret scale calculator to find bridge post distance for a tuno matic bridge
and im just curious why, when i enter 22 frets and a scale length of 24.75
the posts of the tuno matic bridge are spposed to be at 24.811quot; (±0.030quot;) from nut to center of treble-side post. Mount bass-side post 1/8quot; further from the nut.

isnt this a bit far for the scale length of 24.75quot;
can you guys explain why this is so?thanks

If you are building a guitar or drilling for a bridge, are you 100% positive its a true 24.75 inch scale? Alot of scales are called 24.75 but, there are actually like 2 or 3 different scale lengths that are reffered to as 24.75!!!!