Well Smallpatch you're in for some fun. I just last week completed a banana patchbox and fabricated all the spring components...
Basically I followed Ken G's tutorial;
http://americanlongrifles.org/forum/index.php?topic=2613.0You can make the lid opener out of an old hacksaw blade, As Ken recommended I used a spring steel masonry nail (Big Box store) as the release. Begin by annealing both, torch them cherry red and bury them in ashes or sand. Once they cool you can now cut them to size and use files to shape your needed springy things.
That nail requires a lot of filing, the shank must be thin, when you first cut off the piece that will become the nail go ahead and clamp it in a vice and form the head by heating the top to cherry red and careful hammering, be careful that it does not bend one way or the other. Keep an eye on it as you hammer and don't make it too large. Just quench in water when it is to your satisfaction. Now the filing to shape begins, note that the one shown in the photo below is a second nail I made and the head filed differently.
As I mentioned, front to back, you will want the shaft thin, less than a 1/16th. The reason is a thin shank will readily bend whereas a thicker one reseists. Later you are going to temper both the nail and lid lift to bring back the spring steel aspect to both. Unlike Ken I tempered mine by polishing the parts then slowly bringing them up to a deep blue with a torch. You'll recognize that "spring steel" look when you get there, slowly... See the small length of bar stock the nail is sitting on? I polished it too and watched, it will turn before the nail or lid lift, when it got deep straw colored I stopped with the torch and just let it go blue - I quenched in warm motor oil.
Good luck. You won't get much movement out of the nail but it will be enough to allow the lid to spring open. You get one chance to nail the latch into the proper position so be careful, do pre-drill for it and make sure you are dead vertical.
dave
