..Report on the building and ornamental stones of Canada, volI-V . oo o QJ Plate VIII. Telescope Feed Hammer Drill. X. 0H PU 83 Companys quarry near Bancroft, the manager prefers a single bitted drilland uses a 2 inch starter with the heavy machines, and a If inch starterwith the light machines. At the North Lanark marble quarries a 2^ inch+ shaped bit is used with the heavier machines, and a If inch bit for plug andfeathersworkand for gadding. In the granite quarries at Barre, Vt., a 2 inchbit is commonly employed for the deep holes and a | inch bit for plug holes.(Plate X.) Rock drills of th
..Report on the building and ornamental stones of Canada, volI-V . oo o QJ Plate VIII. Telescope Feed Hammer Drill. X. 0H PU 83 Companys quarry near Bancroft, the manager prefers a single bitted drilland uses a 2 inch starter with the heavy machines, and a If inch starterwith the light machines. At the North Lanark marble quarries a 2^ inch+ shaped bit is used with the heavier machines, and a If inch bit for plug andfeathersworkand for gadding. In the granite quarries at Barre, Vt., a 2 inchbit is commonly employed for the deep holes and a | inch bit for plug holes.(Plate X.) Rock drills of the above type are e^ddently too heavy to handle withoutsupport, they are therefore mounted on special contrivances to suit the kindof work in hand. The most commonly used mount is the tripod, the legsof which are supplied with weights to give the whole apparatus great many types of tripod are available, many of which possess especialfeatures and are adapted to particular purposes. For the present purposethe Lewis hole tripod is of interest. This form is supplied with a planedand slotted front bar, so th
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbuildin, bookyear1912
