How to raise a Monolith

Most of you will be familiar with a hydraulic bottle jack, or a screw jack used to raise a vehicle in order to change a wheel. There is little friction, and you apply a small load to the lever over a period of time in order to raise the load.

The Lifting Jack is an even simpler device that uses a short pole and three short planks in order to do exactly the same job.

A better description would be three wedges of hardwood, although only two need to be wedges, the third can have parallel sides.

The central wedge has a hole through it and a loop of strong rope attaches it to the lever pole. The ancients would have used a rope made from sinew, because it doesn't stretch and is very strong.

All three blocks of wood would have been a very hard hardwood such as lignum vitae. This continued in use as an engineering material to make axle bearings for steam engines and other heavy moving machinery in Victorian times and into this century.

The central wedge would be greased on both surfaces. This produces a smooth load bearing surface that could support 10 tons per 6 inch wide wedge without crushing or significant friction - the wedge would fly out unless it is held in place under weight.

The pole is used as a lever with two pivots, alternately above and below the sinew attachment.

After each 10 inch movement of the top of the pole the wedge is pulled out 1 inch, and the block rises 1/30th or 1/20th of an inch, depending on the slope of the wedge.

The other pivot is then packed out to the new postion and the reverse stroke again pulls the wedge out 1 inch, and the block rises 1/30th or 1/20th of an inch, depending on the slope of the wedge.

This is a very efficient lifting device with almost no friction.

A block of 10 tons on each wedge would exert a force equivalent to 6 hundredweight on the sinew rope and 66lbs on the end of the pole. 66lbs is a force that a fit man can easily exert on the pole, and the strain on the wood lever, on the rope and on the wooden wedges are all within reasonable values.

Wedges would more likely be used in pairs from opposite sides of the block so that the forces at each point would be halved.

When a wedge reaches its highest lift position, another wedge alongside would be packed into place and then lift started on the new wedge, so freeing the first wedge.

A working platform

The ends of each packing piece would have holes drilled and as each layer of packing is added to the platform, vertical locking pegs would be dropped in place into the holes, and longitudinal braces would also be pegged in place. The monolith rises on what is effectively a solid block of hardwood.

Using the lifting jack to build a pyramid

Casing the Pyramid

Lifting the monolith of Baalbek

This would exert a force of 17 tons per wedge, so this is getting close to all the theoretical limits for all components of the lifting jack - which may explain why it is still in the quarry!

Why build in monoliths?

When you can cut stones more easily, there is little point in making them smaller unless you have got a very efficient mortar to join them back together again.

But when you develop metal clamps to join stones together it may be more economical to work with smaller stones, and an efficient mortar and efficient stone cutting techniques makes even smaller stones economical.

Hence we quite logically see the earliest monument built from large monoliths. More recently we see smaller stones joined by metal clamps, and the most recent are smaller stones still bedded in mortar.

So the explanation of these building techniques becomes a reflection of developing technology - there is no need to invoke strange powers - at least for monolithic construction!

Wedges classified as ceremonial axes!

Wedges of bronze may also have been used as they make very efficient sliding surfaces when greased. Again look out for 'ceremonial axe'

Herodotus's description of the lifting jack is right - just a few short lengths of wood.

This information is copyright Peter Thomson 2001-2004