This slide carries a head containing a spin dle, similar to a drill-press, and this head re ceives a transverse movement by means of the screw, as shown, the milling spindle be ing driven by beveled gears and a transverse shaft. The cutting or grooving is performed by a face-milling cutter inverted in the end of the spindie, and is fed up and down by means of a screw and small wheel, and when the proper depth for a cut is reached the horizontal movement of the spindle is pre vented by means of a check-nut on the small screw. The sliding or tool head is fed in either direction by means of change feed gears at the end of the screw.
Leeds' Link, and machine (Fig. 13), built by Pedrick & Ayer, of Philadelphia. is used as an attachment either to a heavy milling-machine or a strong drill-press. It will mill out links to any desired ra no dins. It is designed on the principle that the apex of any angle will touch or describe all parts of a circle whose versed sine is equal to the perpendicular where the base is formed by the chord of the arc. It consists of a jointed frame having dovetailed slots running length wise to carry a second frame that has the link-blank secured in it. The second frame is ac tuated by the screw and hand-wheel and describes a circle, according to the angular position of the lower or jointed frame ; flanges are cast on the bottom of the frame for the purpose of bolting down on the table or platen. In the center of the lower frame, at the center of the
joint, is a bronze bushing that is set exactly under the center of the drill-press spindle ; this serves as a lower support for a boring-bar and the shank of the milling-tool arbor. In prac tice it is found more convenient to drill a hole in one end of the link to be slotted, large enough for a boring-bar to pass through ; then, by using a double-end cutter, the slot is cut out to nearly the finished size. The link is then moved along I or I in., and is cut through again until the stock is removed. A milling-cutter similar to a reamer is then used, and the slot is finished to the radius for which the link is set. With this attachment it is claimed that a link 20 in. long can be finished in about 4 hours.
Speed end Feed of Milling-Cutters,—The following table gives the speeds of milling cutters adopted in American practice (see Engineering, December 12, 1800): : see Rolls, Metal-Working.
Mill-Ore: see Ore-Crushing Machines.
Mill-Pug : see Clay-Working Machines.
Mill-Saw: see Saws, Wood.