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Stone shifting 4

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GordonP G
GordonP Sep 7, 2003 17:35:15
Replying to Steve Gray

Looking good, let me get this straight, you've got a rope going from the top of the stone to the top of an "A" frame, with a 3 ton weight hanging in the middle. So the pull on the "A" frame is equal to the pull on the sarsen. It will take some anchoring.

I'm still thinking about levering from the tower, if we do the initial levering with the levers starting at an angle of 45 degrees (instead of vertical or 70 degrees to be more accurate) then the levers will be at 90 degrees to the diagonal bracing logs creating downward pressure on the tower. That way we'll need less anchorage on the tower.

G GordonP
GordonP Sep 7, 2003 17:38:09
Replying to GordonP

At 35 degrees it will be even better and the levers will still work.

S Steve Gray
Steve Gray Sep 7, 2003 19:58:06
Replying to GordonP

No, the rope just goes straight to the ground, no A-frame. Since the monolith is 24 feet high, the centre of the rope will be 12 feet off the ground. We need about 7 tons of tension in the rope, so we need a big stone on the ground to act as an anchor. The lintel might do, epecially if we had some stakes in front of it to stop it from being dragged along. Hey, could this explain some of the mysterious post holes?

Your reduction of the lever angle WILL reduce the side load on the tower. If we have diagonal bracing poles going from the (first) fulcrum to the ground, the ideal angle for the levers would be at right angles to these braces. The angle of the braces will depend on their length and the height of the tower. If the tower is 24 feet and the braces are 34 feet, the angle will be 45 degrees. You could therefore have your levers starting at 45 degrees and the lever load would be transmitted directly down the brace. As the angle reduced, some of the load would be transfered to the tower as a vertical load, which it is well able to withstand. This would, of course, reduce the overall throw of the levers, but I guess we don't care too much about that.