if you have one of those little kits for replacing missing screws on you glasses, dump out the screws and put in some from a old pair of yours.i spent the better part of 20 minutes trying to get a lens in a pair i take on trips as back-up and could not get the supplied screw in the leg hinge.i ended up taking some out a really old set and one of those went in with no problem in seconds.i take that kit on canoe trips and it's a good thing i never had a problem out on the trail,so if you have one in your BOB or whatever replace them with real screws and not the ones from the kit,thats the one with the red top tiny screw driver with the screws in the hollow handle.the driver worked ok.