Tools and Machinery of the Granite Industry

Chronicle of the Early American Industries Association, Inc., The, Jun 2006 by Wood, Paul

Before the advent of carbide tips, drill bits had to be resharpened after about every two feet of drilling. Each drill operator had an assistant who mostly dealt with the drill bits. The drill bits were lifted and placed by the derrick, in front of the bench for the lift holes or on top of the bench for the deep holes. Some of the larger quarry operations used specialized drill-sharpening machines. The large drills used for lift and deep holes were mounted on a channel bar frame (Figure 28) or a tripod drill stand (see Figure 25). The channel bar frame was patented by Henry Sergeant of New York City in 1887. The frame was called a "channel bar" since it facilitated the drilling of a series of holes along a straight channel line. The bar was typically twenty feet long with two legs on each end. This design had a carriage that was driven along the bar by rack and pinion gearing and a circular journal that attached the drill to the carriage and allowed the drill to rotate to different angles-vertical for deep holes and horizontal for lift holes. The carriage location and the drill angle could each be changed without disturbing the other. This design was very popular and seen in many quarries. The most successful of the later pneumatic rock drills were valve-less. One of the all-time best drills, the Joy/Sullivan 360 drifter drill, was valve-less. It had a five- to six-inch diameter cylinder bore and is still manufactured. In the mid-19OOs, using pneumatic drills, it took about two months of drilling to free a thirty-foot by thirty-foot by fifteen-foot-high quarry block. Currently, deep holes are drilled two inches in diameter and spaced three to four inches on center and the quarry blocks are typically thirty to forty feet long by forty feet wide by fifteen-feet high. A pneumatic, double, deep-hole rotary drill capable of drilling two holes simultaneously is used.

Channeling

Channeling is the removal of all the granite along the side and back faces of the quarry block before the block is shot. In the 1860s, a carriage-mounted, steam-driven channeling machine with a linear array of chisels was developed for and successfully used on marble. It was briefly tried on granite but proved less effective for the much harder granite. George Wardwell of Rutland, Vermont (Figure 29), and Ebenezer Lamson of Windsor, Vermont, each applied for patents for channeling machines. Both were issued patents for channeling machines, and between the two, they held thirteen patents for the machine. The two men had an agreement to jointly produce a channeling machine, but Wardwell later backed out. Lamson then designed, patented, and built his own channeling machine. This situation lead to a long, expensive, and acrimonious infringement lawsuit by Wardwell against Lamson, and the court eventually ruled that Lamson had infringed Wardwell's earlier patents.

For granite, the drilling of deep holes and channeling by removal of the granite between the holes (called the core) proved much more effective. A quarry drill with broaching bit (or core cutter) (Figure 30) was used to break out the cores. The broaching bit had a four-inch-wide by one-inch-thick blade with a series of blunt teeth.