Metallurgy Of Cast Iron

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ing chill rolls, car wheels and gun metal, and found no difficulty in having them machined, as shown by the turned bars given with the cuts seen on page 472. The plan adopted to form these swells is simply to place half sections of patterns, as seen at N N, Fig. 126, over the regular test bar pattern when moulding* them; then when the cope is lifted off, they are drawn separately from the mould. Of course, bars can be cast plain their full length and then have a recess about three inches long turned into them, instead of following the swell plan, wherever this is preferable.
The flask's dimensions for casting \}i inch round bars, as seen in Figs. 123 and 124, are to be made eight and one-half inches by ry inches inside measurements and four inches deep. To cast two, one and five-eighths inches or one and fifteen-sixteenths inches test bars, for the second and third standard, mentioned page 533, the only change necessary in the whole system is to make the (la.sk ten inches to eleven inches wide on the inside. If desirable, one flask could be made to answer for moulding either the one and one-eighth inch, one and five-eighths inch or one and fifteen-sixteenths inch diameter bars, simply by having a flask ti inches wide and the holes in the end of the flask at II, Figs. 123 and 124, made one and fifteen-sixteenths inch diameter, also the one and one-eighth inch or one and five-eighths inch test bar patterns to have a swell of one and fifteen-sixteenths inehcs diameter at the point where it would rest, or fill the hole II when the bars are being moulded.
When the strength only is desired, then bars can be moulded in any common jointless flasks for the length of the bars or by ** bedding " them in the floor simplyfter having I''