Fig. 1862.
In [Fig. 1862] is represented a nut threading or tapping machine. The vertical spindles have spring sockets in which the taps are held, so that they can be inserted or removed without stopping the machine. The nuts are fed down the slots of the inclined plates shown on the upper face of the circular base, and the spindles are raised and lowered by the pivoted levers shown. The nuts lie in a dish that contains water up to the level of the bottom of the nuts, the object being to prevent the taps from getting hot and therefore expanding in diameter. Upon the top of the water floats a body of oil about 1⁄2 inch deep, which lubricates the cutting edges of the tap. These machines are also made with six instead of four spindles, which in both machines run at different speeds to suit different sizes of nuts, and which are balanced by weights hanging inside the central hollow column or frame.
Fig. 1863.
[Fig. 1863] represents the socket for driving the tap, so devised that when the tap is strung for its intended length with nuts, the top nut releases the tap of itself, the construction being as follows: s is the socket that fits into the driving spindle of the machine; its bore, which fits the stem of the tap easily, receives two headless screws b, a pin p, which is a sliding fit, and the screw a. r is a ring or sleeve fitting easily to the socket, and is prevented from falling off by screw a. The tap is provided with an annular groove g. The flattened end of the tap passes up between and is driven by the ends of screws b, the weight of the collar ring or sleeve r forcing pin p into the groove g, thus holding the tap up. When the tap is full of nuts the top nut meets face v of ring r, lifting this ring upon the socket and relieving pin p of the weight of r, the weight of the tap and the nuts then causes the tap to be released. By this construction the tap can be inserted or removed while the machine is in motion.
In [Fig. 1864] is represented a rotary nut tapper, and in [Fig. 1865], is also represented a sectional view of the same machine.
The tap driving spindles are driven from a central vertical shaft s, driven by bevel-gear b. The horizontal driving shaft operates a worm c, to drive a worm-wheel in a vertical shaft, which drives a pinion a, driving a spur wheel w in the base of the spindle head, by which means this head is revolved so as to bring the successive spindles in front of the operator. A trough is provided at t to cool the tap with oil and water after it has passed through the nut.
[Fig. 1866] represents a nut tapping machine designed for light work, the spindles are raised after each nut is tapped by the foot levers and rods shown, the latter connecting to a shoe fitting into a groove in a collar directly beneath the driving pulleys of the spindles.