You would not believe how many prints I did for the living hinge enclosure on my lamp. I made one where I accidentally used the length of the outside edge of the enclosure, so the result was too big, I made a couple where I tried to match the “outside edge offset by the width of the living hinge” which were a little too small (something to do with k-factor I suspect). I also was using some not-great plywood from Home Depot which had some voids and some filler and kept breaking.
Some things I learned:
- If you want to wrap an enclosure of thickness t around a circle with diameter D, make the length of your enclosure the perimeter of a circle with diameter around about D+t/2. As I said, there’s probably some fancy k-factor math you could do to get the exact right length, but living hinges can compress and expand a little, bit, so it doesn’t need to be perfect. With really good plywood you can even do just D, but the hinge will be stretched a little bit, so everything will be under tension.
- If you’re having a hard time getting your living hinge to wrap around your enclosure (things are breaking, it won’t bend far enough, etc…) get out a steam iron and liberally blast your living hinge with steam. It will bend much more easily. This is especially true for pieces where you’re going to glue everything in place, because you’re just trying to make a curve, and you don’t need it to “hinge”, but even for hinges it will help.
- I made mine with squared off sides, so I could make the “join” on one of the squared off sides. This made it so the wood wasn’t trying to uncurl and fight against the joint while I was trying to make it. If you have your heart set on a cylinder (and, it’ll be pretty awesome if you pull it off!) I would try maybe printing out a couple of “forms” - like, imagine a square, with a circular hole the same diameter as your enclosure in the middle, then cut that whole thing in half so you have two “U” shaped pieces. You could clamp a bunch of these around your enclosure while the steam dries and the glue dries - should help keep things in place.
- For your project in particular, maybe try some “practice” pieces by reducing the height of your hinge to 1/3, or maybe try printing out 1/4 of the circle to start with - this gives you something you can play with until you get it right, without having to wait an hour every time.
- Most of all, don’t give up. Failure is just finding another way that doesn’t work.
Like I said, I made a lot of prints of my lamp base before I found one that did what I needed it to.