Re: The bluestone debate | Forum — The Modern Antiquarian

Stonehenge and its Environs 134

Image by Mr Hamhead

The bluestone debate

tonyh Nov 18, 2008 20:39:05

Replying to Steve Gray

Steve Gray wrote:

tonyh wrote:

Sorry to correct you but a sledge does not spread the weight. It concentrates it on a smaller area. IE.. The runners..

Tony

Not necessarily. Something similar to a log raft with a flattened underside might be two or three times wider than the stone and would reduce the ground pressure by a proportional amount.

I'm not saying that's how they did it, only that there are ways to solve problems that should not be dismissed out of hand.

But also increase the friction..

Wouldn't dream of dismissing anything out of hand...

Not my style.

Tony

Steve Gray Nov 18, 2008 21:10:01

Replying to tonyh

tonyh wrote:

But also increase the friction..

Not true. It's a popular misconception. Friction depends only on the characteristics of the two surfaces (coefficient of friction) multiplied by the weight. The area of contact does not enter into the equation, except if it changes the characteristics of the surfaces (for example by deformation) and thus alters the coefficient of friction.

Since an increased area actually reduces deformation it also reduces the friction.

There would, of course, be an small increase due to the additional weight of the sledge, but that would be relatively minor in comparison to the weight of the stone and it would be compensated for by the fact that the coefficient of friction of wood is generally less than that of stone.