Spindle
A shaft or mandrel with which to sweep circular moulds in sand or loam. Spindles vary in diameter and length, according to the class of work they are used for. For sweeping ordinary work, the arm to which the sweep is secured is keyed, or otherwise made fast to the spindle, and the latter is made to revolve; but when a vertical motion must be given simultaneously with the rotative, as in sweeping propeller blades, the arm must be free to slide up and down a fixed spindle. A fixed spindle may be made to answer for all ordinary work by securing a collar at the height desired, and allowing the arm to rest thereon as it revolves. When practicable it is always preferable in long spindles to have a dull point at the bottom end, working in the countersunk hole of an iron block that is sunk level with the floor, and the perpendicular maintained by a suitable arm extending from the wall. The method of making spindles with straight sockets and collars is a bad one, as they are sure to work loose ultimately. A much better mode is to turn a slight taper from 6 to 8 inches high, and cast this end in the block in which it must subsequently work--whether it be in a portable tripod or gig, or even in the central portion of the carriage itself. A little oil and fine parting-sand will protect the smooth iron of the spindle end when it is cast, and an absolute fit may be obtained subsequently by grinding the spindle in its own seat with oil and emery. Spindles over 1 1/2 inches may be made of gas-piping, which, when once straightened in the lathe and taken good care of afterwards, are much easier to handle than solid ones, and just as good. The tripod spindle consists of a central hub with three plain arms, equally divided, radiating therefrom; the arms have slot-holes cast in them for bolting purposes. This is a useful tool for bolting to foundation-plates when making sugar-pans and other similar castings in loam; and it is beyond all question the best for setting in the floor, to sweep moulds in green sand. Three blocks on the floor, on which to rest the points of the tripod, with three other smaller ones over them, constitute a very simple contrivance to receive the foundation-plate, the weight of which precludes all possibility of shifting. The gig-spindle consists of a light square frame, with legs, centre hub, and four handles on the corners for carrying it with; this, with a good taper-ended spindle, is extremely useful for numerous uses in both sand and loam. When the use of the spindle is thoroughly understood, a considerable amount of pattern-making may be dispensed with. See LOAM-MOULDING.