Woodwork for secondary schools; a text-book for high schools and colleges, prevocational and elementary industrial schools (1916)
Griffith, Ira Samuel, 1874-1924 · Peoria, Ill., Manual Arts Press · leaf 331
d, one with reference to another: the number ofcastings to be made, the requirements of the pattern asto permanency, economy of time on the part of themolder, economy of time and materials on the part ofthe pattern-maker; ease and economy of time in workingthe castings in the machine shop. If but… … Core Oven. 269. Molding Sand.—Molding sand must be able towithstand great heat and contain clay or alumina enoughto cause it to hold its shape after the pattern is with-drawn. A sand composed of approxi-mately 6 per cent alumina and 90 percent siHca will possess the qualitiesneeded when tempered…
Woodwork (Manual training)
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