Methods of machine shop work : for apprentices and students in technical and trade schools (1914)
Halsey, Frederick A. (Frederick Arthur), 1856-1935 · New York : McGraw-Hill · leaf 165
For work of large diameter a much morecommon machine is the boring mill, of which one of twenty feetswing, by the Betts Machine Company is shown in Fig. 129.Boring mills of large size are frequently made as extension mills—the housings being arranged to be drawn back on the base inorder to increase… … Fig. 129.—Twenty-foot boring mill.
Machine-shop practice
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