Gas Spring Pneumatic Stay 6 kg/13 lbs

Poor instructions

TL;DR instructions have bracket on side of chest upsidedown mount point should be away from lid. Make sure you account for swing of hinge when measuring. I've just completed attaching these stays to a chest I'm building. I decided to go with two lighter stays so that I'd have balance on both sides of the lid rather than only supporting one side. The first one I attached I was slightly low (measured about 3/16" difference between sides after first attempt). I was more careful on the other side and I'm pretty sure I got it exactly as laid out. I finished attaching them and the lid was held open at what appeared to be exactly 90°. When I tried to close, it wouldn't go down all the way by about 30°. I decided to just try flipping the brackets, and that actually got things to close nearly all the way. It was close enough that with pressure on the lid I could get it closed, but I was worried about the forces being applied on the stay, so I drilled out the holes, plugged with dowels, and retried. On the first side that was a bit low, loosening the screws so the bracket had some play seemed to be just enough to get the lid closed, so I moved the hinges slightly down and slightly away from the hinge. After test fitting, things seemed pretty good, so I measured the distance down with a T-square and transferred the mark to the other side. I then attached the bracket to the other stay and pressed the lid firmly up against the first stay, and marked the hole for the bracket. After drilling and screwing the bracket in, I removed the stay, aligned the bracket parallel, and marked the other side to screw in level. It no longer opens to 90°, but the stays are enough to keep the lid open by themselves. Removing one stay from the bracket will cause the lid to close if I'm not holding it up. When the brackets were flipped, it would remain open with only one stay attached. I believe part of my problem in needing to adjust was that I did all my marking with the lid removed as it's pretty heavy when I went back and attached the lid, the hinge causes the lid to move away from the box. So when the lid is open 90°, the back plane of my chest is about 1/8-1/16 in front of the bottom face of the lid. This means when the lid is closed, the lid bracket actually moves a few mm closer to the bracket on the side of the chest. It was extremely frustrating when I first went to close the box and it was left way open. If I ever do another project like this again, I'll be interested to see if measuring with the lid on makes the difference.