"Tim Wescott" wrote in message
...
We have this big ol' pile of horse manure out back, which we can't spread
out in the pasture because it is full of rocks that are just about exactly
the right size for causing problems with horses feet (according to SWMBO,
at least). The sizes range from sand to 3-4 inches.

Since clean, rock-free horse manure is pretty easy to get around here, I'm
assuming I cannot give it away. So I'd like to build a sifter for the
stuff, to separate the good rocks from the good fertilizer.

I'm considering making a big drum with a 1/4" screen, rotating it with
either an electric motor or a Vibration & Stratton engine. I'll load in
dirty manure in one end with my loader, get clean manure out the bottom,
and occasionally dump slightly odiferous rocks out of the drum.

Tim do a little Googling on the types of vibratory sifters that
archaeologists use to find artifacts in 'dig' soil.

They're simple to build, and easy to use. You might check out the College
of William and Mary. They have an active site right now in the Jamestown
area, digging a civil war escarpment.

LLoyd