The Westerly Granite Industry


Babcock-Smith House Museum
124 Granite Street
Westerly, RI   02891
401-596-5704
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Drilling

The "Steam" drill--once powered by steam, later by compressed air yet always referred to as the "steam" drill--was a large drill on a stand; it drilled the deep holes about 4 inches apart. The drill mechanism rotated the bit with each stoke so that the drill would wear evenly. Quarrymen would begin the hole with a fairly large diameter drill about a foot long; when they had reached the maximum depth with that equipment, they would change to a longer bit with a slightly smaller diameter. They would continue with increasing long drills with smaller diameters until they reached the bottom of the granite bed. They used increasingly smaller diameters to prevent the drill bit from getting stuck in the hole.

With deep holes drilled close together, quarrymen could control the break very closely. They would use feathers and wedges about 10 inches long all along the line of deep drill holes to exert a steady even pressure to break the stone free.

Once free, the stone could be rolled over. Note the wood used to cushion the stone and prevent breakage.

Plug drills and jackhammers were used to drill holes of less depth. A jackhammer could drill holes up to 20 inches deep along the head; a plug drill could drill holes 6 inches deep usually along the rift. Note the evidence of the deep hole drilling that shows where large pieces of granite have been quarried. Drill bits of varying length are in in the background.

 

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