i cant find an answer for this, on the tuning key, it has a little tightening screw, how do you know how much to tighten it without damaging the bushing or whatever's inside? TIA, john
A quick way to get a "feel" for such things.... Put your screwdriver on one of the other screws and see how much pressure it takes to back it off a bit and then to re-tighten.

That will give you a rough approximation. These screws just hold the key in place, and like most such they are easy to strip. Be careful.
thx- i see a plastic washer between the actual turning key and tuner body- i know i didnt want over pressure it, i wasnt sure just how tight is normal, and if it matters being adjusted strung or unstrung
The screw shouldn't affect the plastic grommet, the only ones that can be tightened have a metal nut instead of a grommet. Those rarely need adjusting. The screw you're referring to is just to hold it in position, the best way to go is use a very small or jeweler's screwdriver, and only tighten it if it moves with almost no pressure. It's only there to hold it in position, and doesn't take much to tighten it. As the previous poster said, check some of the other screws to get a feel for how tight it should be.
Hmmm...I wonder what this button does...
Actually, I believe the plastic washer is there to prevent metal to metal rattling, should there be slack in the key mechanism.

As far as adjusting the screw on the key, just rock the key back and forth while you tighten the screw. When you get to the point where you can't feel any gear lash, you're there.

Put another way, the key shouldn't have any slack travel in it, before it starts to adjust in the opposite direction. If you go past that point, you'll start to feel binding, which is not good. It means the gears are too tight.
Cranky you and I are talking about 2 different screws, I was thinking of the one on the housing that's just a locator. Forgot about the one on the key itself, that's what you're referring to and that's the same way I adjust them when [rarely] needed.
Hmmm...I wonder what this button does...