I grew a few dozen confectionery sunflowers (the kernel eating kind) and was wondering if anyone has come up with a way to shell sunflower seeds in an efficient manner on a small scale?
I just built a contraption that uses a shop vacuum on the exhaust setting to bang the seeds around in a wooden box that theoretically knocks the hulls (shells) off with the seeds dropping to the bottom of the box and the hulls being blown out a chute. I found the plans for this on the internet from an article in Mother Earth News magazine from the 1970's. The contraption failed miserably not cracking open a single seed with the seeds (kernel in shell) just piling up in one corner of the box.
Could you use a 5 gallon bucket with a lid, the a long shaft with two pieces of chain welded to the end, and then run the shaft up through the hole and chuck it into a drill. Put a bunch of seeds in the bucket and then give the drill a spin and see if it beats off the hulls???
This has been the subject of much tinkering at my house. I think I've come up with a design, but about the time I thought it through enough to start building, I lost my workspace. Long story.
But, the basic design is a set of rollers, set up so that they turn at different speeds. Each roller is wrapped with a silicone mat. Finding the right mat takes some trial and error. Some of the ones sold as hotpads work, but the texture is the crucial part. You need a texture that will grip the shells, but won't hold the debris after the shells have cracked. There's a store near me that has these garlic peelers that work perfectly: https://www.vanillabeanonline.com/store/p288/Garlic_Peeler.html
They're only $3 a piece, but the shipping costs more than the peelers.
Anyway, choose the direction of the wrap so that the rollers aren't shoving debris under each other's edges. They need to turn so that the surfaces facing each other are moving in the same direction, but at different enough speeds that they rub the shell apart. I'm guessing a 1:2 ratio would work well, but I haven't tested it. I was looking for the right kinds of gears to use when I lost my workspace. I hope to pick this project back up next summer.
I have tried using these same sheets on something like a grain grinder, but it was harder to keep the plates steady enough, and the motion if the auger resulted in a lot of debris being pushed under the edges, prying the sheets off their plates. But, it did crack the shells without crushing the seeds, so I was definitely on to something.
This would also work to remove the hulls from various grains. I know the grinder model worked to dehull several cups of lambsquarters seed before it started having problems.