(From H. P. Gillette) ───────────────────────────────────┬─────┬─────┬─────┬─────┬─────┬───── Diameter of cylinder in inches │ 2¼│ 2½│ 2¾│ 3⅛│ 3¼│ 3⅜ Length of stroke in inches │ 5│ 6│ 6½│ 6⅝│ 6⅝│ 7¼ Length of drill from end of crank │ │ │ │ │ │ to end of piston │ 36│ 43│ 50│ 50│ 50│ 52 Depth of hole drilled without │ │ │ │ │ │ change of bit, inches │ 15│ 20│ 24│ 24│ 24│ 24 Diameter of supply inlet. Standard │ │ │ │ │ │ pipe, inches │ ¾│ ¾│ ¾│ 1│ 1│ 1¼ Approximate strokes per minute with│ │ │ │ │ │ 60 pound pressure at the drill │ 500│ 450│ 375│ 350│ 325│ 300 Depth of vertical hole each machine│ │ │ │ │ │ will drill easily, feet │ 6│ 8│ 10│ 14│ 16│ 20 Diameter of holes drilled, inches │ ¾ to 1½ as desired Diameter of octagon steel, inches │ ¾ to│ ⅞ to│ 1 to│1⅛ to│1⅛ to│1¼ to │ ⅞│ 1│ 1⅛│ 1¼│ 1¼│ 1⅜ Best size of boiler to give plenty │ │ │ │ │ │ of steam at high pressure, │ │ │ │ │ │ horse-power │ 6│ 8│ 8│ 9│ 10│ 12 Best size of supply pipe to carry │ │ │ │ │ │ steam 100 to 200 feet, inches │ ¾│ ¾│ ¾│ 1│ 1│ 1¼ Weight of drill unmounted, with │ │ │ │ │ │ wrenches and fittings, hot boxed,│ │ │ │ │ │ pounds │ 128│ 190│ 265│ 315│ 385│ 390 Weight of tripod, without weights, │ │ │ │ │ │ not boxed, pounds │ 80│ 160│ 160│ 160│ 210│ 275 Weight of holding down weights, not│ │ │ │ │ │ boxed, pounds │ 120│ 270│ 270│ 285│ 330│ 375 Cubic feet of free air per minute │ │ │ │ │ │ required to run one drill at 100 │ │ │ │ │ │ pounds │ 92│ 104│ 126│ 146│ 154│ 160 ───────────────────────────────────┴─────┴─────┴─────┴─────┴─────┴───── For more than one drill, multiply the value in the above line by the following factors: For 2 drills, 1.8; 5 by 4.1; 10 by 7.1; 15 by 9.5; 20 by 11.7; 30 by 15.8; 40 by 21.4; 70 by 33.2.