Plug and feather

Multiple sets of plug and feathers are typically used to split a single, large piece of stone.

A number of holes are then cut or drilled into the stone face along the scored line approximately 10 to 20 centimetres (3.9 to 7.9 in) apart.

Bronze plugs and feathers were then driven into grooves which had been previously cut with a chisel and mallet.

[5] On Dartmoor, Devon, England, the process is known as feather and tare and it was used from around 1800 to split the large blocks of granite found on the ground there.

In New England, the plug and feather technique is first mentioned in The New-England Farmer; Or, Georgical Dictionary (1790) by Samuel Deane.

Deane wrote: "... another method of breaking rocks, which ought to be generally known, and which sometimes turns out cheaper, is this: Drill two holes in a stone, ranging with the grain, when that can be discovered with the eye.

"[7]: 268–269 In 1803, Lieutenant Governor Robbins of Massachusetts was a member of a committee that had been tasked with building a new state prison.

In a chance encounter during the same year, Robbins came into contact with Mr. Tarbox, who was using a modified version of the plug and feather method that had been described by Deane.

The working principle of the plug and feathers
A stone being split using a single plug and feathers