Pattern making and foundry practice; a plain statement of the methods of wood pattern making, as practiced in modern pattern shops, with complete instructions for sweep work and notes on foundry practice, together with numerous drawings taken from actual patterns .. . t least y^rT^ three feet long, SX^yX^^, and slightlybeveled toward the edges, with a head 2iXifastened securely at right angles to the most approved form of joint for a T-squareis shown at a 6, Fig. 13, A tapered dovetailedwedge is glued to the blade of the square with >-- Dove, tail we^j9«- -I 1^ . E ri3 IS the grai
Pattern making and foundry practice; a plain statement of the methods of wood pattern making, as practiced in modern pattern shops, with complete instructions for sweep work and notes on foundry practice, together with numerous drawings taken from actual patterns .. . t least y^rT^ three feet long, SX^yX^^, and slightlybeveled toward the edges, with a head 2iXifastened securely at right angles to the most approved form of joint for a T-squareis shown at a 6, Fig. 13, A tapered dovetailedwedge is glued to the blade of the square with >-- Dove, tail we^j9«- -I 1^ . E ri3 IS the grain of the parts running at right angles toeach other. A corresponding notch or mortise ismade across the head of the square, which allowsthe blade to be taken out of the head and truedup. The joint can be better secured by the useof a few round-head screws, if desired. The 42 PATTERN MAKING set squares or angles are used to draw parallellines, at right angles to the blade of theT-square; or to draw such angles as appear inthe corner of the set squares (see Fig. 14). Thefirst of these set squares contains an angle of 45°in two corners and an angle of 90° or a rightangle in the other. This is used to lay out octa-gons, or to bisect the right angle, producing a. Fi^ i<i miter joint. The second one contains angles of30°, 60° and 90°. This square is employed tolay off the hexagon, or bisect the angles of thehexagon in order to obtain the hexagon third one contains angles of 22^°, 67J° and90°, and is used to bisect the angles of theoctagon, obtaining the octagon miter (see a 6 14). Some few extra large wooden set AND FOUiNDRY PRACTICE 43 squares are yet in use for certain purposes; butfor general use the modern celluloid or amberoidinstruments are so far superior, on account oftheir transparency, that the wooden ones havefallen into disuse. A set of mathematical instruments may bebought for from $ to $ or more, accord-ing to the fancy of the purch
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Keywords: ., bookcentury1900, bookdecade1900, bookpublisherchicagofjdrakeco
