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I'm new to SS construction & the rules of thumb I've developed form building classicals do not necessarily apply. What amount of action increase can be expected between the no-strings condition to fully tensioned strings? Of course, details of neck construction, stiffness of neck materials, string tension, scale length, etc., all play a role, so I'm looking for some kind of range, or what to expect based on construction. My current neck is pretty much standard: one-piece, no lamination, 22 mm thick at 1st fret, 26 mm thick at 9the fret, double-action TR.

sorry cant be much help but il ask anyway
are you just talking about neck movement and not about bellying of the top ?

Hard to give an answer as not all wood or construction methods are the same. Neck bolck and UTB play a huge role there.Stiffness in wood can veri from piece to piece. I do try to build with the stiffest wood i can find for minimal movement. I also laminate my necks, but the top stiffness and braceing are the main concerns for movement and movement in some places can be a good thing.A trussrod can take up most all the slack in a neck. Scale length and string size will also affect it as well.With this said, i believe not all guitars will have the same amount of difference from being strung or not.

Yes, I agree with all of this. I expect there to be as many answers as there are guitars. But I'd like to see some numbers that people observe. Perhaps, folks don't measure no-tension action, so the data are not out there?

On my last dozen or so guitars this is what I have found. With a neck built straight and the slack taken up on the truss rod without causing any back bow... Once strung up, I usually end up with 6 -10 thou of fingerboard relief. Once strung up, I usually wait at least one day before checking the relief.
I usually laminate my necks & always use 2, 1/8" X 3/8" CF bars. Neck material doesn't seem to make much difference. I use Bigleaf maple, H. mahogany & Black walnut & all seem to behave similarly.

I'm not sure my original question was phrased carefully enough, so I'll try again.

For whatever reason, a straight edge placed on the frets is higher at the bridge now (neck glued) than before gluing the neck. So the guitar seems destined to be a low action guitar, but how low, I don't know. That's not necessarily going to be a problem for fingerstyle playing. Here's the information I'm looking for:

1. With no strings on the guitar, measure the action with a straight edge resting on the first fret and on the saddle. In this case, the action is defined as the distance between the top of the 12th fret & the bottom of the straight edge. We will call this ACTION No. 1.

2. Now string up the guitar, wait for it to settle in & repeat the action measurement. Fret the string at the 1st fret to be consistent with step 1. We will call this ACTION No. 2.

3. Now calculate Delta = ACTION No. 2 - ACTION No. 1. This is the number I'm interested in.

When building classicals, I follow David Schramm's method of putting two 2-1/2 pound weights on the upper bout, supporting the guitar at the head plate, & measure the difference in action. This simulates (approximates) what happens when the strings are tensioned. If I do this for the SS, what weight should be used?

Well, when setting up a guitar, you always leave the saddle high so you can set the action appropriatly. I get my measurements with strings at full tension of the gap between 12th and string bottom, figure out each strings action I want and then subtract that from the gap. What I'm left with I double and remove from each string location at the top of the saddle. I've not got my ideal action. Then I set the intonation.

Don't try and figure out the action height and make the saddle to suite without strings at full tension.

I hear your main question though. What you really need to do is make sure the neck is set right before you attach the neck to the body. With no frets on the board (board glued onto neck and neck shaped) I like the plane to rest on top of the bridge or just a hair higher. No more than 1.5/64". With frets on, not much more than 1/16" and just a hair under is better (to my liking)

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I'm with Rod on the basic approach, but as I like a bit taller saddle, I like about 1/16 above the bridge with no frets on the FB. I've also found that the guitar will continue to "settle in" for a while so I don't get in a hurry for the final set up. I play the guitar for at least a week before setting the final action and then recommend that the client bring it back after a couple of months and let me set it up again. It's wood, after all...

When I asked the man who taught be to build guitars what this should be, he simply said "experience will tell you what your guitars require". He was right.

Good luck,

Chuck

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Thanks, Rod & Chuck. Looks like I should be OK. With frets on, my clearance at the bridge is 0.066". A smidgen more than 1/16. I can sleep better now.

This is going to vary a whole lot depending on how you build. I'm come to figure about 1/16" rise in the top from string tension. Zero from neck joint flex.

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