“It is interesting also to note how little this quality of solidity adds to the cost of castings. The addition is merely so much more pig-iron and really not that, because in the stove-plate style the forms are more complicated, the patterns more expensive and frail, and the cost of molding is greater. But what signifies even a considerable increase in the first cost of a tool that in daily use is to perform the work of many and is to place its possessor on a mechanical eminence? “It is not the purpose of this paper to enter into details, interesting and important as these are, but to draw attention to the subject in a general way. The improvement observed quite recently in this respect, as well as in other points of tool construction, is highly gratifying and encourages the expectation of still further and more general progress.” The following summer I employed some of my leisure time in making the plans for a couple of machine tools. One of these was a double-drilling machine for boring the boxes of connecting-rods, there being then no such machine in existence to my knowledge. I had been planning such a machine in my mind as long ago as when I was in the works of Ormerod, Grierson & Co., in Manchester, England, in 1864-5. This tool was designed first to bore the two boxes simultaneously and rapidly, and, secondly, to bore them with absolute accuracy in their distance apart and in the intersection by their axes of the axis of the rod at right angles in the same plane, and all this without measurement or setting out or the possibility of error. The other tool was comparatively a small affair. I utilized an old milling-machine for facing simultaneously the opposite sides of nuts and taking the roughing and finishing cuts at the same time. The ends of the nuts were first faced on a special mandrel which insured their being normal to the axis of the thread. A string of these nuts was then threaded on a mandrel fitting the top of their threads and some 15 or 18 inches long, on which they were held against a hardened collar, the diameter of which was equal to the distance between their opposite finished faces. The cutting tools were set in two disks about 12 inches in diameter; they were set about an inch apart alternately in two circles, one about one eighth of an inch inside the other, and were held in position by set-screws in the periphery. The cutters in the outer circles did the roughing; those in the inner circles were set projecting about 0.001 of an inch beyond the roughing tools and finished the surfaces. The mandrel was set between centers, and the string of nuts was supported from the table at the middle of its length. The nuts were secured in position by a dividing plate on the forward center-bearing. What was done with the two drawings I will state presently.