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Assuming you have relief set. And nut slotted close. I think I stumbled into an obvious idea. With strings open, measure height at 12th fret. To get where u want to go (assuming action is too high of course, and u are shaping the original saddle), use difference of measurement and goal height, multiply by two and take that off the saddle height. It will get u very close. Why? Similar triangle math. These measurements need to be made at high and low E. it's a little more complicated if action is too low, requiring a new saddle. But the original saddle can be used as a template. Add 2x measurment difference to make a taller saddle.

This won't get you there precisely, but it will get u very close.

Mike

This is how we make a compensated saddle and adjust height, pretty common practice

http://www.kennethmichaelguitars.com/saddle.html

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Ken Cierp

http://www.kennethmichaelguitars.com/

Yup, I do it all the time.

Yep very common practice with set-up routines that folks use:

1) Set relief
2) Cut nut slots (nut slots can be cut completely independent of the action height and can be finally cut too since we take everything else out of the equation by fretting and holding between the 2nd and third). By eliminating one of the set-up variables, the nut slots the remaining variables can be addressed sequentially.
3) Measure action at the 12th
4) determine desired action (there are specs for generic action, Martin specs and others) and player technique can and should have a say here too. I'll add that string gauges also impact what successful..... action measurements are achievable.
5) Whatever needs to happen at the 12th from our measurements is doubled at the saddles since the 12th is roughly half the scale length.
6) Mill or adjust saddle(s)
7) Observe and remeasure (one of the reasons that the doubling is not always exactly what we want is reducing the height of the saddle also reduces the torque on the saddle, bridge and consequentially the top pull-up and this slightly skews the results one way or another.
8) Bill the customer and get the money....

Easy peezy

Many Luthiers arrive at this on their own. It's also a method that's taught and we teach it in our classes.

Even though the results are not always exactly the function of the doubling it's so very close that it's usually just about right. For electrics with "set flat" trems or hard tail pieces it is closer to exact than it is with acoustics.

One other variable because the strings pull differently at different action heights is the relief. Lowering action can reduce string pull, seemingly.... on the headstock because we are also changing the angle of the pull by lowering the saddles. As such I always recheck relief after dropping saddle height and tweak as necessary.

Related discussions include Martin specs for setting action, how various string manufacturers may intonate differently for the same gauge strings, player technique and the Robin Hoods of the world who think they are shooting a bow and arrow and impact on string lash of string gauge which can be surprising. Understanding string inertia is a good thing to do.....

Hesh, every time I do a setup I am so glad I took the course with you and Dave. There are dozens or maybe hundreds of tips during that two days that have helped so much. Thanks again for doing them and I hope you guys get a new batch of students soon.


Sent from my iPhone using Tapatalk

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Hesh, exactly what I do, except Step 8. You must be talking about paying customers? I'm not familiar with that step.

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Joe Beaver
Maker of Sawdust

I agree it's not an exact measurement. Be conservative with this. But, it really is a good rule of thumb.

With nut and saddle corrections, the error can be huge...almost 3/10,000 of an inch! I am not certain I could send a guitar out the door with that sort of shabby workmanship.

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