Every time I adjust the height and tighten the screw, either the laser head will drop or it drops when I frame my project. I have tightened the screw as much as it'll tighten so I have no  idea what to do? It didn't do this for the first maybe 7-8 times I've engraved something. I did buy this engraver about 2 years ago but have not used it up until last month… if that makes a difference. I have the xTool D1 10X engraver.

Any help would be most appreciated!