Way back in the 80s, Fred bought a 13k lb. horizontal mill. On the day it arrived the only lift he could borrow was rated at 11k. For unknown reasons, I was always the designated driver when it came to these iffy lifts. It took full back tilt and four human counterweights (including Fred) to get it high enough to pull the truck out from under. As I began ever-so-gently lowering the mill, Fred told one of the counterweights to jump off and put some timbers under it. The combination of the changing CG and loss of 120 lbs on the back was enough. As the back wheels came up I hit full down on the mast, to no avail. The mill crashed to the concrete then tipped to one side, landing on the end of the table. This freed the forks, which bounced back up and flipped over into the transport position, vibrating like tuning forks with me right between them. Once I got off the lift, it was an hour before I could stand without help.