So I bought a 91 450s the other day. I know it has the edge tremolo. The owner of the shop offered to do free set up. I reminded him the the edge has the lock screws and he didn't know what I was talking about. He said he has already lowered it. Hopefully he won't again as it was decently low already. My question is how much damage could he have caused by not lossening them first before he lowered it and must i take them all the way out to know for sure?? I haven't picked it up yet. When I get it should i take it apart and see?

He would not have been able to lower it if the studs were locked down.

So assuming he didn't heman the thing then maybe they weren't locked down properly??

Maybe previous owner didn't lock them because he didn't know about them too.

Exactly. The locking studs are probably loose, and you should lock 'em down.

Ok. What is the Allen size again? Just tighten to slight resistance and done?

1.5mm. Yes.

1. Loose the locking studs
2. Adjust (rising or lowering) the trem studs.
3. Tighten the locking studs (just finger pressure)
4. Carefully, tighten again the trem studs as if you wanted to lower them a little bit. Just finger pressure.

That is the way they work and you get the most tuning stability; just tightening the locking studs doesn’t work at its best.

For loosening them again you need to rise a little bit the rrem stud first to decouple the locking studs. The finger pressure on a 1.5 mm should not be strong enough if they are correctly blocked.

When you retighten the trem studs (after loosening lock stud and setting action) how much further down will the trem go? To successfully lock them together you have to account for that last little twist on the trem stud. So keep the trem just a HAIR above where you want it to sit in its permanent position before you twist and lock them together?

Funny! I had to give someone the heads-up on this on the AZ just yesterday. They don't advertise that they have them at all I don't think.

The difference in the action height after retightening the trem studs is negligible; you will notice that it goes down just a little bit until it gets completly blocked by the locking stud, but I don’t feel any change in the action height to make me set up the trem a little bit higher expecting it goes down to the correct position after retightening the studs.

Ok got it. Thanks for the help. I appreciate it.

Depending on how hard he tried, he could definitely get them too damn tight though.