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 .. . 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
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 .. . 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 purchaser. The very. Tin /sr cheap ones are not desirable, and in buyinginstruments or tools it is always advisable toprovide the very best that ones means will per-mit. An indifferent mechanic can never do goodwork with inferior tools and a good one will notuse them when he can possibly avoid it. Theset shown in Fig. 15 has fairly good points and 44 PATTERN MAKING will answer very well for persons of limitedmeans. A set of this kind retails for about$ and will answer every purpose for the classof drawings required in the pattern shop. In making up the working drawings for shopuse it is preferable to trace the outlines faintlywith a sharp, hard lead pencil. After this hasbeen done the drawing can be brought out withink or a soft, black lead peacil. When the draw-ing has been plainly brought out, some drafts-men give the cores or core prints a yellow tintand darken the parts which are to be not only improves the appearance of thedrawing, but has additional advantages, espe-cial
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Keywords: ., bookcentury1900, bookdecade1900, bookpublisherchicagofjdrakeco
