legs are 2x4's, 30" long - make 4 per sawhorse. Note chamfer on one end - this prevents binding when opening sawhorse.
Step 2: First side, step 1
fasten plywood to two of the legs - note position of chamfers.
Step 3: First side, step 2
drill holes (for pivot point)
Step 4: Second side, first step
hammer 16 penny nails into the other two leg at the pivot points (make sure the chamfers are positioned correctly). cut the heads off the nails, leaving one inch. instert the nails into the holes in the other legs (see picture).
Step 5: Second side, step 2
fasten the second piece of plywood to the second set of legs
Step 6: Last step
drill holes to attach stop rope (I didn't draw the rope, because I was to lazy to figure out how to draw a knot with Google Sketchup!) just take a piece of rope about a foot long, stick it through the holes, then tie a knot in each end (or tie it like I did in the photo of the folded sawhorse, laying on the ground, on the first page).
Step 7: Rope stop
OK, I got off my lazy butt and figured out how to draw a rope stop - here it is.
Step 8: You're done!
stand the sawhorse up and spread the legs apart as far as the stop rope will let them go. I've had a pair of these for twenty years, and they're still plenty strong.