Machine drawing; a practical guide to the standard methods of graphical representation of machines, including complete detail drawings of a duplex pump and of a direct-current generator . gth can be conveniently made in even inches withoutany fractions; viz, 28 inches. It will be noticed that the stuffing-box flanges serve to centeithe yoke in line with the steam and water cylinders. This is adesirable feature of construction, and forms a simple and easymethod for lining up the steam and water ends. PLATE Q. VALVE MOTION DETAILS Piston=Rod Levers. The piston-rod levers on this plate arespecifi
Machine drawing; a practical guide to the standard methods of graphical representation of machines, including complete detail drawings of a duplex pump and of a direct-current generator . gth can be conveniently made in even inches withoutany fractions; viz, 28 inches. It will be noticed that the stuffing-box flanges serve to centeithe yoke in line with the steam and water cylinders. This is adesirable feature of construction, and forms a simple and easymethod for lining up the steam and water ends. PLATE Q. VALVE MOTION DETAILS Piston=Rod Levers. The piston-rod levers on this plate arespecified to be steel forgings. Forgings of this kind are expensive,but are light, neat, and reliable for the important service which theyhave to perform. Castings, whether steel or iron, are much cheaper,and perhaps more commonly used for this detail. When soundthey are equally serviceable, though of more clumsy proportions;but the danger in castings of this form is the existence of hiddenflaws or pockets, which frequently occur at the points where thehub or the fork joins the arm. These flaws cannot be readilydetected from the outside, and breakage may occur at some 194 MACHINE DRAWING. MACHINE DRAWING 195 critical time, when the disability of the pump may be a seriousmatter. Dimensions Out of Scale. It will be noticed that on thedetail of the link pin two of the dimensions have a short wavy,line beneath the figures. This is one of the several ways of indicat-ing that the dimension is out of scale. Some draftsmen use astraight dash beneath the figure; some draw a circle about it; someprint after the figure, out of scale. Although workmen are notallowed to scale drawings, but are required to work to figures only,yet for general safetys sake, and for the sake of the draftsmen whoconsult the drawings frequently, attention must be called to anyvariation of the figure from the measured distance on the makes a workman, or any one else who reads a shop draw-ing, lose confid
Size: 1314px × 1901px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpublis, booksubjectmachinery
