Originally Posted by GroovinOnFunk
I'm not sure the size... but i was working on mine today and its definitaly a MIA local hardware store size.
same size as the allens on the saddles actually.
btw, what does that screw lock in exactly? because I had it in without realizing it and was still able to move the saddles up and down (lowering and tightening the action)
I don't remember the size either but this is right. I lost mine and got another one at the local hardware store, so it's some common size.
What that screw does is lock the saddles to the large "U" frame of the bridge. It doesn't particularly lock up and down movement, but it is to press the saddles together and to the frame. The idea (a cool one at that) is that in traditional bridges the saddles sit on the thin screws that are the height adjustment so as the strings vibrate the saddles also because of this thin support can vibrate too which fails to transmit all the energy and tone to the bridge body and hence to the wood of the bass body. By clamping the saddles in the bridge frame it provides a path for sound with much more area (sides of saddles instead of points on tiny height screws) into the body of the bass. I believe this was one of Leos last ideas. The clamping action, however doesn't really hold the saddles down which is done by string tension.