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I just got off the phone with a builder that uses an available bridge setting gauge. He is having lots of issues with intonation so I thought this may be a great topic for discussing.

I threw away my stew mac gauge as it never gave me a good result. So this is what I learned

1 https://www.youtube.com/watch?v=EJG5Frbu78c
there is a 2nd part for this on you tube so watch them both
In a nutshell if I can help anyone here to understand this we have to know the variables of the equation.
There are 2 and it is simply that we know the top will move but how much will it
2nd is we also know the bridge will rotate again we don't know how much.
the neck will also move but we can help control this with the truss rod.

So the video covers most of this but here is something I will pass on to help you understand this . So get a fretboard and glue this to a 2 by 4 or something that is reasonably stiff. Only need a few frets so put frets in 1 5 12
these 3 frets can tell you a lot.
you can use a nail or a tail piece to hold the string and we only need to work the #1 and #6 string

So my rule of thumb is to go nut to 12th fret times it by 2 and add 1/10 of an inch.

so how and where do we go from here ?? Easy if you are making a higher action guitar for a hard pickin blue grass player you measure to the front of the saddle and a finger picker you go to the back.
In plain words shorten it for softer playing and lengthen for harder playing.
As the guitar settles in you will have room on the saddle to lengthen the string length to clear sharp and also a touch of room to shorten for flat
by making this little jig you can play with the intonation and understand the variables so your next guitar won't have these issues. This is one of the points of building that you can,t beat a good yard stick. Not every process needs a jig.
Learn this exercise and you will be a better builder and set up.

"if you are making a higher action guitar for a hard pickin blue grass player you measure to the front of the saddle and a finger picker you go to the back. In plain words shorten it for softer playing and lengthen for harder playing."

It took me a while to reconcile the two statements above.

Are you saying that you measure scale length plus rule-of-thumb 1/10" to the front of the saddle for a hard flat picker, which slightly lengthens the string by the thickness of the saddle, and measure scale length pluse rule-of-thumb 1/10" to the front of the back for a finget picker, which slightly shortens the string by the thickness of the saddle?

So 1/10" + 1/8" (saddle thickness) to the center of the saddle for a flatpicker and 1/10" - 1/8" (saddle thickness) to the center of the saddle for a finger picker?

As a side question, your video shows you working on a 25.4 scale guitar. My StewMac fret slotting template is 24.9 on one side and 25.34 on the other, and they said that the 25.34 is sometimes called 25.4 and they don't offer a template at 25.4. I realize the difference is small, but it is there. Again, side question, but which do you use - 25.34" or 25.4.

Ed

Yes ed
think of it this way the higher the action the more you bend the string so the more adjust ability you need in the saddle. I hate the stew mac jig I have seen so many misplaced saddles because of this.

there is another point and this is where do you get your finger board. NEVER ASSUME THE SCALE LENGTH IS TRUE TO MARTIN. That is why I measure nut to 12th fret following the line of the strings of 1 and 6.

John, you should offer the "bridge system location tool" again. It works great for this stuff. I do need a calculator to convert the 16ths to 10ths of an inch though.

I wish I had the time I have 20 in process for 10 yr I would like to finish I still rely on the ruler myself just out of habit I guess
We will be shooting more video soon and may address this issue

I figured I am only working with mostly one scale length - 24.9 - so early on I made a jig. I just made my first 25.34 (nominal 25.4??) neck, so I made a .44 spacer to make it longer. Here is a shot of the jig, then a couple with the extension on it:

https://www.flickr.com/photos/ruby1638/ ... 488198220/

Click right and left and text below. It hooks over the nut cavity and the side of the saddle rests against it - note that the 25" mark at the end is to the center of a 1/8" thick saddle. This forum only allows 1 URL per post, so I could not show the nut end - it is just a small piece of wood glued on hanging down into the nut slot

It was easy enough to make that I will make another for a significantly different scale length. All you need is a square (I used a semicircular compass) to ensure it is correct at the centerline of the top and this jig, Easy peasy

Ed

be wary of the jig as you may not realize depending where you get the fretboard they may not be the same . Play it safe use your jig but still measure to be sure.

Not a problem since I slot my own fretboards off the same jig each time. But yes, check if you bought it.

Ed

tippie53 wrote: I hate the stew mac jig I have seen so many misplaced saddles because of this...

Would that be the adjustable long rod jig with the pins, or the saddle slot jig?
Thanks for the information, it's extremely helpful.

the bridge a matic I think they call it . it has the 2 pins