This gives an example of a small portable hand powered shaker table one could build using some old bicycle parts and a few misc pieces of hardware. I can't find where I put the link, but I've also seen additonal home brewed shakers that are motorized as well.
Either way the mechanics are simple. Using either a motor or by hand, you shove the table sideways, then "snap" it back. The thin sheet of water flowing over the table washes away any lighter material that "jumps" during the snaping action. Or at least that's the way some have described the action as being. So while I understand in principal how it works, there is one thing I have yet to figure out.
And that's the angle of the riffles. You'll notice in the hand opperated table, the riffles run straight across. Where as the "professional" modles angle them. I figure, keene and other companies have done the research, there must be a reason why they angle the riffles like that above and beyond being a convient way of sorting the fines as they flow across/down the table. It looks to me like a very shallow angle, say of 15-20 degrees from being square to the edge. Anyone have a table that you may care to share what angle the riffle would work best at?
My other question is the size of the riffles. Sadly, I don't live in one of the major gold belts in America, I'm just outside of Chicago. Any gold found around here or neighboring states will all be placier/alluvial gold that was dragged down out of canada during the last ice age. What folks on the coats call flour gold we concider nearler pickers! LOL Gold around here is more like talc then it is like flour. What little is mentioned about riffles in some of what I've read about building a shaker table, one person said he used 1/8" wood strips placed 1" apart.
Concidering what I said about the gold in these parts, would I be better off using smaller riffles or perhaps placing them closer together? Or even a combination there of? Any other suggestions or comments about building my own shaker table? I've a few ideas for a "shock absorber" but I'm open to any other ideas...