My solution: a gardening sieve. With a bit of leftover steel mesh and some hand-me-down meranti planks from the garage and some brand new steel screws, I hacked up a wooden frame to both hold the mesh rigid and to prevent material from spilling over the edge. I did this with my el-cheapo Ryobi table saw (more on that later), but you can build this just as well with a hand saw, or even no saw. You could even use logs and nails if you had to.
I added the diagonal corner pieces because the frame was too wobbly for my liking without them. The mesh was originally about twice the size of the sieve as it is now, which would have been unwieldy. In fact the sieve is just the right size now - neither too big nor too small, so I can comfortably hold it and shake the soil/gravel mixture to separate them, as you can see here where I have a little pile of gravel piling up.
The rigidity of triangles for the win. What's the deal with that, anyway? In a triangle each corner's movement is constrained by the (connection between the) other two corners, whereas in a quadrilateral the neighbouring corners have no such constraint, I guess: one may freely change the distance between those points anywhere from zero to (sum of side lengths) by folding the two sides connecting the neighbours.
ReplyDeleteThat kind of mesh works great for gardening, by the way: keep it dry and it'll last a good while. (Existence proof: my father built one of these, many moons ago).
In fact the diagonals have only one screw attaching them to each side; I didn't expect the frame to be as rigid as it turned out to be: I thought the sides of the triangle would still rotate about the pivot (the screw) slightly without needing to change the length of any side too much. I think the mesh itself also provides much of the rigidity when the diagonal can transmit the forces from one edge to another.
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