I have one Kahler and I let it float, so I don't know for sure. But on mine I'm pretty sure that one of the allen bolts engages a "stopper" that is basically a trem block. It stops it from pulling up past a certain point, or neutral if you set it that way. But I vaguely remember that being one of the differences between the spyder types, or lower model cam units, and the "pro's." So you might not have it. Actually, the crappy Korean Kahler ripoffs had it, but they broke after about a year anyway. One way to block it altogether is to replace each spring with solid brass stock with two precisely drilled holes, or one wide piece with all 4 holes drilled. Or you could drill a through hole to the back of the guitar, install a "tee nut" inside the cavity, and have precise allen bolt adjustment over the stop mechanism. You just have to locate the hole right.