Hexagon Turret Lathe with Patent Chasing Saddle.-A machine intended for chuck work mainly, either in cast iron, steel, or bronze, is illustrated in Fig. 99. The spindle is made hollow to receive bars up to 2 in. diameter, when it is desired to turn pieces direct from the bar.

The headstock is fitted with duplex gearing, which can be thrown in or out while the lathe is running, and which is so arranged, in conjunction with two speeds on the countershaft, as to give six properly graduated speeds for each step of the cone pulley. By changing the position of the belt eighteen speeds are available. It will be noticed that this machine is of a compact design, the bed being extended to the floor line beneath the fast headstock to give rigid support.

There are two saddles, each carrying a turret. The main turret is hexagonal, each face has a tool hole for holding shank tools, boring bars, etc., large tools for repetition work being bolted directly to the faces of the turret.

The turret is set at an angle to allow long tools to clear the pilot wheel, but all the tools are true to the centre line when brought in straight alignment for action. There is an independent stop fitted for each face of the turret; these trip the feed automatically, and also act as dead stops.

The square turret mounted on the front saddle has room for four tools, and is fitted with a patented mechanism for chasing, by the action of which it is claimed that both external and internal screw threads can be accurately and rapidly cut without the possibility of cross threading. This chasing motion is entirely independent of the feed

motions.

These machines are in use in a large number of the leading workshops, and by motor-car engineers for producing gear blanks, and parts of the transmission mechanism of motor cars.

These parts are usually inade from large pieces cut off from round bars, or from large drop forgings. On suitable work it is estimated that one turret lathe will displace five to six ordinary engine lathes.

A "Brass Finisher's' Turret Lathe.

This lathe is shown in

Fig. 100. It is fitted with a two-jaw self-centering chuck on the spindle, and at the opposite end carries a gear communicating motion to a guide

screw through pinions. Working on the screw is a die which operates through a shaft a turn-over slide rest.

The slide rest carries the chasing tool, which is only used for chasing, and when not in use is turned over on its axis, i.e. the back shaft.

The guide screw and die are both movable, and are substituted when a screw of different pitch requires to be chased; thus the different screw threads are cut without the aid of change wheels. The changes of cutting, turning, and boring are in this arrangement effected with ease and facility.

The turret can carry a full complement of tools for any specific work, and thereby effects a considerable saving of time after once fixing. Internal and external screws, with right or left hand threads of 8, 11, 14, 19 and 28 per inch (which are the standard pitches) can readily be cut by simply changing the guide screw and die. The concentric chuck is not always used, but chucks having three or four jaws;

universal, or independent, or "bell" chuck may be fixed on the spindle as required.

Capstan Lathes.-The lathe illustrated in Fig. 102 is also fitted with a special saddle for chasing square or vee threads by means of a "leader" (screw).

Four different pitches, either right or left hand, can be cut by each leader, the change being made by levers. By means of a frictional arrangement on the headstock, the back gearing may be removed and single speed introduced without having to stop the spindle. The capstan slide has an automatic feed, and is fitted with a dead stop for each tool. The spindle is hollow, and will take bars up to 2 in. diameter; when,