osha, Wis., has recently patented an improvement in countersinks to boring tools, which is illustrated in our engravings. Fig. 1 is a side ele- springs. to the straight and curved portions of the chimney. The Fig. 5. brushes in this case are pressed outward against the chimney by bringing the… … the air which circulates between pipe and flue to the rooms screws in keeping them in position. F represents the cutting above, into which it escapes through suitable registers. points or bits of the countersink. They are in form about a Fig. 4is a simple form of quarter section of a cone, and…
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