Part 12 (1/2)
=General Description of a Turret Lathe=--The turret lathe shown in Fig
1 has a hexagonal shaped turret _A_ with a hole in each side in which the tools are held This turret is mounted on a slide _B_ which is carried by a saddle _C_ that can bethe bed to locate the turret slide with reference to the length of the tools in the turret and the rooitudinally by turning the pilot wheel or turnstile _D_, or it can be fed by power Ordinarily, the hand adjuste when the tools are not cutting, although sometimes the hand feed is preferable to a power feed when the tools are at work, especially if the cuts are short After a turret tool has finished its cut, the turnstile is used to return the slide to the starting point, and at the end of this backward movement the turret is automatically indexed or turned one-sixth of a revolution, thus bringing the next tool into the working position The turret is accurately located in each of its six positions by a lock bolt which engages notches for at the turret base A binder lever _E_ at the top of the turret stud is used to cla
The forward movement of the slide for each position of the turret is controlled by stops at _F_, which are set to suit the work being turned
When parts are being turned froh the hollow spindle of the headstock and extends just far enough beyond the end of the spindle to per one of the parts The bar is held while the turning tools are at work, by a chuck of the collet type at _G_ This chuck is opened or closed around the bar by turning handwheel _H_ After a finished part has been cut off by a tool held in cross-slide _J_, the chuck is released and further_K_, and the bar which passes through it, to be drawn forward This forward ainst a stop gage held in one of the turret holes, to insure feeding the bar out just the right a the next piece On some turret lathes, the lever which operates the chuck also controls a power feed for the bar stock, the latter being pushed through the spindle against the stop
The machine illustrated has a power feed for the cross-slide as well as for the turret The motion is obtained from the same shaft _L_ which actuates the turret slide, but the feed changes are independent The cross-slide feed changes are varied by levers _M_ and those for the turret by levers _N_ For s, etc, a jawed chuck is screwed onto the spindle and the work is held the saine lathe So castings of irregular shape, or special work-holding fixtures which are bolted to the faceplate The s the bed when this is necessary in order to feed a tool sidewise
This particular machine is driven by aThe necessary speed changes are obtained both by varying the speed of the ears in the headstock The ears are shi+fted by the vertical levers shown
While many of the features referred to are coeneral, it will be understood that the details such as the control levers, arrangement of stops, etc, vary on turret lathes of differentTurret Lathe Tool Equip]
=Exas 2 and 3 show a turret lathe operation which is typical infor an automobile and it is machined in two series of operations The first series is shown by the plan view, Fig
2 The casting _A_ is held in a three-jaw chuck _B_ Tool No 1 on the cross-slide is equipped with two cutters and rough faces the flange and end, while the inner and outer surfaces of the cylindrical part are rough bored and turned by co tool No 2
This tool has, in addition to a regular boring-bar, a bracket or tool-holder which projects above the work and carries cutters that operate on the top surface Tools Nos 3 and 4 next cohed out by No 2, and No 4 finish-facing the flange and end of the hub The detailed side view of Tool No 3 (which is practically the saement of the cutters _C_ and _D_, one of which turns the cylindrical surface and the other bevels the end of the hub The hole in the hub is next finished by tool No 5 which is a stepped reamer that machines the bore and counterbore to the required size within very close limits The surfaces machined by the different tools referred to are indicated by the sectional view _E_ of the hub, which shows by the numbers what tools are used on each surface
For the second series of operations, the position of the hub is reversed and it is held in a spring or collet type of chuck as shown by the plan view Fig 3 The finished cylindrical end of the hub is inserted in the split collet _F_ which is drawn back into the tapering collet ring by rod _G_ (operated by turnstile _H_, Fig 1) thus closing the collet tightly around the casting The first operation is that of facing the side of the flange and end of the hub with tool No 6 on the cross-slide, which is shown in the working position A broad cutter _H_ is used for facing the flange and finishi+ng the large fillet, and the end is faced by a smaller cutter _I_ When these tools are withdrawn, tool No 7 isthe outside of the cylindrical end (preparatory to cutting a thread) and rough boring the hole These saement of tools Nos 7 and 8 is shown by the detailed view Tool _J_ turns the part to be threaded; tool _K_ turns the end beyond the threaded part; and tool _L_ bevels the corner or edge The rea position for finishi+ng the hole and beveling the outer edge slightly At the same time, the form tool No 10, held at the rear of the cross-slide, is fed up for beveling the flange to an angle of 60 degrees The final operation is that of threading the end, which is done with die No 11 The boring-bars of tools Nos 2, 3, 7 and 8 are all provided with pilots _N_ which enter close fitting bushi+ngs held in the spindle, to steady the bar while taking the cut This is a co turret lathe tools
The feed of the turret for both the first and second series of operations is 1/27 inch per revolution and the speeds 60 revolutions percuts and 90 revolutions percuts The total tis complete is about 7-1/2the work in the chuck
=Machining Flywheels in Turret Lathe=--Figs 4 to 6, inclusive, illustrate how a gasoline engine flywheel is finished all over in two cycles of operations First the flywheel is turned complete on one side, the hole bored and reamed, and the outside of the rim finished; in the second cycle the other side of the flywheel is co 4 First Cycle of Operations in Finishi+ng Gasoline Engine Flywheels on a Pond Turret Lathe]
During the first operation, the work is held by the inside of the rim by means of a four-jaw chuck equipped with hard jaws The side of the ri circuh-turned, using tools held in the carriage toolpost The hole is then rough-bored by bar _C_, which is supported in a bushi+ng in the chuck, as shown in Fig 4 The outside of the wheel rih-turned at the same time by a cutter held in the extension turret tool-holder _T_ (Fig 5), and the taper fit on the inside of the flywheel is turned by4) held in a tool-holder attached to the turret
The outside of the wheel ri
5) held in an extension turret tool-holder the sa tool _T_ At the sa-bar _D_ (Fig 4) The side of the rim and the hub of the wheel are also finished at this ti cutters _H_ and _K_, held in tool-holders on the face of the turret When the finishi+ng cuts on the ri taken, the work is supported by a bushi+ng on the boring-bar which enters the bore of the wheel, the boring cutter and facing tools being set in such relation to each other that the final boring of the hole is co cuts are taken
[Illustration: Fig 5 Elevation of Turret and Tools for Finishi+ng Flywheels--First Operation]
The web of the wheel is next finish-faced with the facing cutter held in the holder _E_, and the taper surface on the inside of the rim is finished by the tool _L_, at the same time While these last operations are perfor arbor _J_, which enters the bore of the wheel The bore is finally rea” rea operation is coroove _N_ is cut on the inside of the rie toolpost The first cycle of operations on the flywheel is now completed
The flywheel is then removed from the chuck, turned around, and held in ”soft” jaws for the second cycle of operations, the jaws fitting the outside of the wheel ri the finished surface of the rim) The operations on this side are very similar to those performed on the other side First, the side of the rih-turned, using tools held in the carriage toolpost The inside of the rim and the web are then finished by a cutter held in a tool-holder at _P_, Fig 6, which is bolted to the face of the turret The work is supported during this operation by a bushi+ng held on a supporting arbor _U_, having a pilot which enters a bushi+ng in the chuck Finally, the ri cutters _R_ and _S_, the work being supported by an arbor, as before
[Illustration: Fig 6 Second Cycle of Operations on Flywheel]
These operations illustrate the methods ee nuine flywheels, etc,a Flywheel at One Setting in Turret Lathe=--The plan view _A_, Fig 7, shows an arrange a flywheel co The hole for the shaft has to be bored and reamed and the hub faced on both sides The sides and periphery of the rim also have to be finished and all four corners of the ri this work consist of boring-bars, a rea heads on the , in this case, three tools) and a special supplee at the extre is held by three special hardened jaws _b_ in a universal chuck These jaws grip the work on the inner side of the ri roo the chuck body or jaws Three rests _c_ are provided between the chuck jaws The work is pressed against these rests while being tightened in the chuck, and they serve to locate it so that the arms will run true so far as sidewisewith relation to the stops for the turret and carriage_r_ of suitable dia-bars in the main turret, as will be described
In the first operation, boring-bar _ht in line with the spindle and is entered in bushi+ng _r_ in the chuck Double-ended cutter _n_ is then fed through the hub of the pulley to true up the cored hole
While boring the hole, the scale on the front face of the riht into action to rough turn the periphery, after which tool _e_, in the wing rest, is fed down to clean up the back face of the rim As soon as the scale is removed, the hole is bored nearly to size by cutter _n_{1}_ in bar _m_{1}_, and it is finally finished with rea_ and _h_, in the facing head, are next brought up to rough face the hub and rim, and round the corners of the rim on the front side This operation is all done by broad shaving cuts The facing head in which the tools are held is provided with a pilot bar _t_ which fits the finished hole in the flywheel hub, and steadies the head during the operation The cutters _f_, _g_ and _h_ arethe for the desired di operations