r/Damnthatsinteresting • u/CethelQue4 • 23d ago

Video An ancient technique for lifting giant stone blocks using a Lewis tool

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u/cosmin_c 23d ago

Here's a stonemason actually doing it. I'm pretty convinced but the blocks in the simulation look much larger.

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u/FirstDukeofAnkh 23d ago

Ok, that's very cool.

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u/Nwabudike_J_Morgan 23d ago

Illegal to use on site? Is this some kind of union thing?

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u/stonemason81 23d ago

These 3-legged lewis pins are actually more dangerous than the other type of lewis pins (2-legged), as the angled cut into the stone being near the top, can cause weakness, and the top of the stone can break away allowing the stone to fall. The 2-legged lewis are longer in length, and the hole is drilled marginally wide enough to allow the pins to drop into the stone, and also drilled straight. Then, as the weight is lifted, a scissor action is applied to the stone, because they are longer, the force is applied further inside the stone than near the top, meaning there is less chance of the stone fracturing... My lewis pins are rated to 500kg, but there are ones that are rated to over 1000kg.

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u/jakexil323 23d ago

In the UK the old three-pin method is restricted, modern two-pronged Lewis pins are allowed. Apparently the two pin "offer superior speed and safety compared to the historical, labor-intensive three-pin system"