Didn't really document the design but have a look at http://www.geocities.com/diannebest/camera/camera1.html bottom of the page and http://www.geocities.com/diannebest/...ra2.index.html also bottom of the page.
The only thing that doesn't show clearly in the pictures is how the legs attach. I took a piece of 2x12 and cut the "Y" from a solid block.
The pan surfaces are cut from 3/4" ply. The upper disk has a recess (only about 1/16") that leaves only the circumference to contact the lower disk.
For really CHEAP, it is incredibly solid. I have used MANY tripods over the years and the only commercial tripods I have used that are more rigid were intended for TV studio cameras.
It may be "primative" with its wingnut clamping, and it doesn't offer "roll" movement" but it is solid as an Oak stump!
You can of course, adapt the tilt to suit your camera's bed.