I have the impression that I have been (since October) experiencing a constant (sometimes even overnight) increase of action height in my uv70p.
It is true that this guitar went under many stages, sent back to germany, returned with basically nothing more than a nice setup, was diagnosed to have truly insufficient neck/body joint, possibly longer neck screws than the ideal length, etc.
Basically when I had the guitar back from germany, it had a nice action and setup, but the neck was shifting from day to day downside, giving a very short margin between the fret ends and the strings on the treble side. Also I could move the neck by my hands easily, while presumably fully bolted. I didn;t like this. Also when I had attempted to tighten the stock screws, the headstock-side ones would strip heads, while the rest two (bridge-side ones) would just turn a little bit more. This raised the action, i suspect due to tightening the two long ones. I didn;t like all this, obviously, that's why I moved to the fix described here : http://www.jemsite.com/forums/showpo...&postcount=267
The guitar for all those days since then was very stable, as far as the parallel to the body motion of the neck is concerned. I have been measuring the same exact clearances all those days. The neck indeed now seems stable. Does not shift downside. However, yesterday, when i tried to tighten the back screws a little bit (to see if the joint was stable), I noticed that the two bridge-side screws (where the original longer ones would go), would turn a little bit. This might have raised the action. So I setup the guitar again, and I lowered the bridge once again. As always plays very very sweet.
Problem in the back of my head, tho, is that I have been practically lowering the bridge height for as long as I remember and almost always it would marginally increase again 1-2 days latter. I measure this with both filler gauges, and a special pick i have for this. My "benchmark" is a pickboy pick on 24th fret A string. If it sticks on the strings or not, is a sign of a change. I have always been locking the stud afterwards with the smaller alen. What would all that mean? Ok, in the first months the guitar had severe joint instability issues, but now it is pretty stable. Winter ok, has been going a little bit stronger, snowed on the mountain near our house, but then again i cannot get much sense out of it.
What would this all mean? This does not give me the impression of being truss rod's business. Didn;t get wild deviations on relief across checks or setups.
Would it mean:
- the neck joint that still has issues?
- the paper shim compressing, giving larger angle and increasing action height ?
- trem studs are loose ?
- the basswood compresses ?
- the maple compresses ?
- trem springs react to temperature?
- strings react to temperature? (will need to replace those)
- wood changes size by temperature?
next time i open up the trem, I will have to fully assess the situation with the studs.
One thing that I read over ibanezrules.com site, is that after tightening the smaller alen in the studs, one has to also give the larger alen (stud) a little bit of torque just to have it sealed against the lock. I didnt do that, might it be that this would make a dramatic change on the locking effect?