Pins are placed into drilled holes at 45 degree. Holes should be the size of the pins with no slop. Then you connect a chain to them for lifting.
A machine can now lift and place stones with ease.
To order a set check out Trow and Holden
“... the listed size of the pin lewis (eg. 7/8”) should be the hole size drilled to receive the pins. The pins are slightly undersize to fit in a standard hole – there should be no “slop” nor should it be necessary to drill an oversize hole to accommodate the pin.
“...should also be aware that a worn or incorrectly ground drill will often result in an undersized or misshapen hole. Using a new drill bit is recommended.”
“It is also important that the holes be drilled to a minimum depth to receive the full pin length (eg. a 7/8” pin lewis would need a 5” minimum depth hole). The full pin length must be fully set in the hole before any lifting is attempted.”
Trow and Holden Co.