The principles of pattern making, written specially for apprentices and students in technical schools (1900)
Horner, Joseph Gregory, 1847-1927 · London, New York, Pitman · leaf 109
A; andin addition it is also frequently necessary to joint theteeth at a-a, as shown, because the under cutting ofthe outsides of the teeth would often prevent themfrom being drawn backwards together. In suchwheels, therefore, the block A is lifted first vertically,and the blocks B, each carrying… … Fig. 74. riated Wheel. Then their central portions are made with ring cores,from the box, Fig. 75. These are set in the mouldwithout prints, and the space between them corres-
Patternmaking
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