So with the clean guitar tuned to pitch and truss rod adjusted in my lap I measure the high e and then the low e and return the guitar to my bench. I then write down what the action is and I annotate it as “IA - 5.4 and 7.2 meaning high e is 5.4/64th” and the low e is 7.2/64th”. “IA” means to me initial action even though it’s not how it came in. I like to record the initial action which is not really the initial action since we already lowered the action perhaps substantially by cutting the nut slots properly and adjusting the truss rod of which more times than not is a reduction in relief bringing the action down as well.
If it occurred to you that action is not about the truss rod or the saddles, etc but instead a combination of relief, nut slots and saddle height(s) give yourself a gold star you're right. And doing them in that order if that occurred to you you get two gold stars.
The picture I took is very difficult to take when you are alone. I had to hold the guitar in the playing position, the camera in one hand and the engineer’s scale in the other hand. I do know the scale is a bit cooked and skewing the read.
So when I look at what we have in real life without the camera I can be sure to have the scale level on the two frets and move my head around to different angles to see what the measurement really is. In this case the low e on one of my living room guitars is 5.5/64th”. This is not the guitar we are working on this pic is only a reference.
So my recording of the action at this stage really has one purpose and that is to have this as a reference when I mark the saddle for material removal.
So here is what you will want to record and perhaps print for your shop wall. These are the action specs that I have set over 16,000 guitar to and with that resulted in a very small return rate and lots of happy clients.
The acoustic guitar specs here originally came from Martin and the rest are simply what Dave and I do and find work very well for folks. Electric guitar specs will be provided in the electric guitar set-up tutorial if that gets to happen…
Be advised these action setting are a function in the sequence I have taught here of having adjusted the rod and cut the nut slots first before ever measuring action the 12th. If you do this out of sequence you will have to do it twice…. or more.
Six String Steel String Acoustic Guitar
OOO or similar or smaller bodies 12’s:
4 and 5.5 (high e first and in 64th of an inch)
Dreads w/12’s:
4 and 6
OOO and similar of smaller with 13’s:
4 - 4.5 and 5.5 - 6
Dreads w/13’s:
4.5 and 6.5 - 7
There is wiggle room here and I use it. If I know someone is a hard hitting bluegrass player I will go on the higher side.
If I know someone has a light touch and is a finger stylist I may go on the lower side especially with 13’s which are harder to play.
And before someone pops in and says they can go lower, good for you so can I but I find in my experience that unless you know the attack and player style it may not work for everyone to go lower.
In my world the three guitars that I will set-up tomorrow will all have action considerably higher than I am quoting here. Whatever we do is often a vast improvement for folks.
For a 12 string steel string acoustic guitar we go lower on the action and it’s pretty OK if the ax is a bit jingly and rattles a bit that’s part of the 12 string vibe.
So for a dread sized guitar 12 string I might go <4 and <5 if that specific guitar will do this without issues. Again a little rattle is OK on a 12.
For an acoustic bass I might go 5 and 7
So I wanted to point out that there is an inverse relationship between the nut slots and the saddles for action height. If I lower the nut slots it also reduces the action at the 12th by 1/2 the amount that I lowered the nuts slots. The same is true of the saddle when I lower the saddle the action at the 12th gets lowered 1/2 the amount that I lowered the saddle.
What’s important here is this is why we cut the nut slots very early on and maintain a properly adjusted truss rod so that when we measure at the 12th and approach the saddle to correct what we see nothing else matters but the saddle now. We also can’t add material to the saddle so it’s important to observe the sequence of the set-up.
Lastly for this post this inverse relationship with the nut and saddles in respect to what happens at the 12th fret is critical to understand when setting up a guitar.
So since the 12th is located at 1/2 of the “speaking length” of the strings, the distance from the face of the nut to the break point on the saddle any height change at the saddle is seen as half that at the 12th where we always measure action.
For example if in this example I want to on the bass side of the saddle for the low e reduce the height of the saddle from 7.2/64th” to 6/64th” or 1.2/64th” of reduction at the 12th fret I now want to lower my saddle under the low e twice that amount or 1.2/32nd”. Please note that the fractional denominator has changed from 64 to 32.
The same holds true for the high e if I want to go from what we read in the playing position as 5.4/64th” to 4/64th” I want to lower action at the 12th fret by 1.4/64th”. This means the saddle will come down on the treble side under the high e double what I need at the 12th fret or 1.4/32nd”. Again the denominator changes as the distance doubles.
Make sense, we double what we need to gain or lose at the 12th fret when we address the saddle?
