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I have been doing this a long time. Over 25 yr. Here is what I can share about setting up a bridge/saddle location

A the most important thing is to identify the variables you are working with

So what are they?

First and foremost is the set up your planning to use. After all a set up for a finger picker is different than for a flat picker.

action height is the other variable , string gauge , top movement etc. Saddle width, neck relief.


I hate using jigs for this task I prefer to use a 36 in scale. ( nice way to say expensive yard stick )


So what is the best way ???

If you don't know how to figure scale length you will know to measure nut to 12th fret times 2 , so no matter what your using , Martin scale, gibson etc it is still the same,

so X represents scale length.

no you have to work some compensation length , so in a way , your working scale length ( static dimension ) to working string length ( dynamic dimension ) this is always changing and can be seen as you do tuning,

so what you want to do is plan in for this adjustment in the saddle so you can ( COMPENSATE) the saddle to get the best intonation per string.

No guitar is spot on the day you string it up. The top settles in , the bridge will rotate and thus the saddle location changes under the stress of the strings from a non stressed condition.

So with this all thrown at you , I found that a good compensation length is about .10 of an inch set to the center of the saddle slot. So if your building a Dred for a flat picker , you may move this point closer to the front of the saddle slot.

so with all of this , I know if I tune up the guitar after my adjustments , on the day I set this up I like to see about 2 cents flat. Then as the top settles in and the bridge torques forward, I should see the saddle roll forward and after about 2 to 3 weeks I can then make my compensation adjustment to the saddle. The guitar will never go flat to the set up created as the action height will rise through age causing things to go sharp , relief goes up again cause sharpness , so you can adjust all this in and make a very tight intonation on a guitar. Its all in the understanding of the physics of what moves and how.

So if you plan that you know you need to work in some movement on the saddle , the final tweaks can be made by intonation adjustments in the saddle as it falls into its final location as the guitar accepts the applies stress. Also know that RH will cause movement but that is a variable that comes and goes so try and set up the guitar for the condition it will be living in, Fla will get a bit different set up that one guitar to Arizona.

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Good write up, John. I’ve never read this info before. I guess this is why people recommend giving the guitar a month or so after the initial setup to “settle in” and then set it up again.
Thanks again for the detailed description.

I've been doing the initial setup, cutting the break angle on the saddle more towards the back of the slot. It gives me room for any needed adjustment down the road. I guess we end up doing the same thing, but in a slightly different way.