[Fig. 669] represents an improved hand lathe by the Brown and Sharpe Manufacturing Company, of Providence, R. I. It is specially designed for the rapid production of such cylindrical work as may be held in a chuck, or cut from a rod of metal passing through the live spindle, which is hollow, so that the rod may pass through it. Short pieces may be driven by the chuck or between the centres of a face plate (shown on the floor at e) screwing on in the ordinary manner. When, however, this face plate is removed a nut d screws on in its stead, to protect the thread on the live spindle.
The chuck for driving work in the absence of face plate e (as when the rod from which the work is to be made is passed through the live spindle) may be actuated to grip or release the work without stopping the lathe. The pieces j j are to support the hand tool shown in [Figs. 1313] and [1314], in connection with hand turning, the tool stock or handle being shown at k on the floor. The lever for securing the tailstock to or releasing it from the shears is shown at t. The tail spindle is operated by a lever pivoted at g so that it may be operated quickly and easily, while the force with which the tail spindle is fed may be more sensitively felt than would be the case with the ordinary wheel and screw, this being a great advantage in small work. The tail spindle is also provided with a collar r, that may be set at any desired location on the spindle to act as a stop, determining how far the tail spindle can be fed forward, thus enabling it to drill holes, &c., of a uniform depth, in successive pieces of work.
The live spindle is of steel and will receive rods up to 1⁄2 inch in diameter. Its journals are hardened and ground cylindrically true after the hardening. It runs in bearings which are split and are coned externally, fitting into correspondingly coned holes in the headstock. These bearings are provided with a nut by means of which they may be drawn through the headstock to take up such wear in the journal and bearing fit, as may from time to time occur.
It is obvious that the lathe may be removed from the lower legs and frame and bolted to a bench, forming in that case a bench lathe.
Fig. 670.
[Fig. 670] represents a special lathe or screw slotting machine, as it is termed, for cutting the slots in the heads of machine or other screws. The live spindle drives a cutter or saw e, beneath which is the device for holding the screws to be slotted, this device also being shown detached and upon the floor.
The screw-holding end of the lever a acts similarly to a pair of pliers, one jaw of which is provided on handle a, while the other is upon the piece to which a is pivoted. The screw to be slotted is placed between the jaws of a beneath e; handle a is then moved to the left, gripping the screw stem; by depressing a, the screw head is brought up to the cutter e and the slot is cut to a depth depending upon the amount to which a is depressed, which is regulated by a screw at b; hence after b is properly adjusted, all screw heads will be slotted to the same depth.
The frame carrying the piece to which a is pivoted may be raised or lowered to suit screws having different thicknesses of head by means of a screw, whose hand nut is shown at d.