What? What are ferrules? They're those little thingers you use to attach steel cable to itself. (Go look at a steel cable-bike lock - the loops you put the lock through are made using these) The way they work is simple enough, just slide the two cables through, and use a tool with LONG handles to crush the ferrule to pinch the cable. I guess it's okay for bike locks, 'cause they're not load bearing, but the directions on the last package of ferrules I bought (after I ran out near the end) suggests not using them on vinyl coated cable. What the hell, I figured, they probably don't really mean it - so I went ahead and did it anyway. They did mean it. A few weeks after I built this whole contraption, a friend and his girlfriend visited from Wisconsin. I figured that I could fit on the sofa a lot easier than they could, so they could go ahead and use this bed. The pair of them, obviously, weighs more then I alone do, and it did NOT take long for one of the connections to break - the ferrule maintained it's grip on the vinyl coating, and the cable slid right out. Luckily, this was not all that important a link, and they didn't fall (but I wouldn't have been able to raise the bed, had I wanted). We unhooked the bed and they slept on it, on the floor. The next day I went and got some uncoated cable, more ferrules, and stops, and stuff. It didn't take long to rethread it (with some minor design improvements, even) and it's been working great ever since (that was 8 months ago, as of the writing of this). Uncoated cable's cheaper and easier to get in big lengths anyways.