A Lewis Lifting Pin is one of a category of lifting devices used by stonemasons to lift large stones into place with a crane, chain block, or winch. It is inserted into a specially prepared hole, or seating, in the top of a stone, directly above its center of mass. It works by applying principles of the lever and utilizes the weight of the stone to act on the long lever-arms which in turn results in a very high reaction force and friction where the short lever-arms make contact with the stone inside the hole and thereby prevents slipping.
Lewis Pins are used to lift large stones with a crain,chain block or
winch. The pins are inserted into specially prepared holes, or seated,
in the top ofstone directly above its center of mass. Pins are liable to
slip out of the seating if some of the weight of the stone becomes
in-balanced. For this reason, a
safety sling should always be used together with the Lewis Pins.
• Always check that the stone is not edge bedded.
• The hole the stone must be deep enough to take the full length of the Lewis Pin and be no more than 1mm larger than the pin.
• Drill at a 45-degree angle
• Before inserting the Lewis Pin, ensure that the hole is free of dust and any water or slurry (which can cause the Lewis Pin to lose grip an slip out of the hole.
• The lifting hook must be the correct size for the Lewis Pin (not too big).
• When lifting, do not snatch lift. Take the weight slowly and carefully to ensure a proper lifting.
• NEVER drag the stone sideways as it can bend Lewis Pins.
• NEVER work underneath hoisted stone.
• NEVER place your hands underneath stone.
• NEVER pull stone towards yourself, putting yourself in a trap area between stone and solid objects (walls, steelwork, plant or equipment, etc.).
• NEVER swing stone over areas where others are working/walking.