Fig. 711Fig. 711.
Fig. 711.
The stop motion for the forward motion ofm, and that therefore determines the length of turret traverse forward, and hence the distance each tool shall carry its cut along the work, is shown inFig. 711. The end of the screwaabuts against the stopbin the usual manner; it is, however, threaded through the eye of a boltc, as well as through the end of the turret slide, so that it may be locked by simply operating the nutd. Thus the use of a wrench is obviated, and the adjustment is more readily effected.
Fig. 712Fig. 712.
Fig. 712.
Largeimage(92 kB).Fig. 713Fig. 713.
Largeimage(92 kB).
Fig. 713.
Figs. 712and713represent a screw machine by the Pratt and Whitney Company, of Hartford, Connecticut, and having Parkhurst’s patent wire or rod feed for moving the work through the hollow spindle and into position to be operated upon by the tools. The reference letters correspond in both figures.
Atais the front and atbthe back bearing, affording journal bearing to a hollow spindlec, which carries the shelldof the work-gripping chuck, the clutch ringhand a collari, in which is pivoted, atj, the clutch leversg. This collar is threaded uponcand is locked in position by a ring lock nutj′. The clutch armkslides upon a rodx, and has a feather projecting into a spline inx. The coreeof the work-gripping chuck is fast upon the inner spindlef, which revolves with the outer onec. The left-hand end offabutsagainst the short arms of the clutch leversg, and it is obvious that whenkis operated back and forth uponx, it moves the clutchhendways uponc, and the cone uponhoperates the leversg, causing them to move the inner spindlefendways and the inner coneeof the chuck to open or close. Suppose, for example, thatk(and henceh) is moved to the right, and the long ends ofgwill be released and may close moving their short ends away from the end off, and therefore releasingefrom its grip upon the work. In movingkto the right the sleevelis also moved to the right, and its serrations atl′being engaged with the tonguep, the sleevemis pulled forward. Now the bar or rod of which the work is made is held at one end by the chuck, it is supported by the bushingzin the end of spindlec, and in the bushingsin the arm of sleevem, while it has fast upon it a collart. When thereforemis pulled forward or to the right, its arm meetstand pulls the rod or bar for the work through the chucke.
On the other hand whenkand thereforeh,l, andm, are moved to the left, leversgare opened at their long ends by the cone ofh. The short ends ofgpush the inner spindlefto the right,epasses throughd, and being split, closes upon the work and grips it, the parts occupying the positions shown in thefigure. The same motion ofkpasseslthrough the sleevem(the teeth atnraise the catchp, allowingl′to pass throughm) so that at the next movement ofkto the right,mwill be pulled a second step forward, again passing the work through the chuck.qis merely a pin wherewith to liftpand enablemto be moved back, when putting in a new rod for the work;kis operated by a link fromutov, the handle for moving this link being shown atwin thegeneral view.
To prevent the sleevemfrom moving back withlit is provided with a shoeo, pressed by the springragainstx, thus producing a friction betweenmandxthat holdsmwhilelslides through it.r′is to regulate the tension of the spring atr.yis merely a sleeve to protect the clutch mechanism from dust, &c.
Box tools for screw machines are used for a great variety of special work. They are simply boxes or heads carrying tools and a work-steadying rest.
Fig. 714Fig. 714.
Fig. 714.
Fig. 714represents a box tool for a screw machine. The cylindrical stem fits into the turret holes and contains a steadying piece or restgto support the work and keep it to its cut. In the box tool shown in the figure, there are four cutting tools set in to the depth of cut by the screwsa,b,c, anddrespectively, and a fifth for rounding off the end of the work is shown ate.
Fig. 715Fig. 715.
Fig. 715.
Fig. 715aFig. 715a.
Fig. 715a.
Fig. 715bFig. 715b.
Fig. 715b.
Fig. 715represents a top view,Fig. 715aa front view, andFig. 715ban end view, of a box tool for shaping the handles for the wheels of the feeding mechanism of machines. The work is first turned true and to its required diameter, and the rest is set to just bear against the work to steady it and hold it against the pressure of the cut. The cutter is cylindrical with a gap cut in it atg, so as to give a cutting edge. By grinding the face of this gap the tool is sharpened without altering its shape, as is explained with reference to circular or disc tools for lathe work. The cutter is provided with a stem by which it is held in the slide, through the medium of the clamp. The slide is operated by an eccentric on the spindle or rodr, which is operated by the handleh. The stop obviously arrests the motion of the slide when it meets the boxb, and this determines the diameter of the work, which is represented bywin the end view figure.
Fig. 716Fig. 716.
Fig. 716.
Fig. 716represents the die holder and die for the Pratt and Whitney Co.’s screw machine. The die is cut through on four sides, and is enveloped by a split ring having a screw through its two lugs, so that by operating the screw the die may be closed to take up the wear and adjust it for diameter. It is secured in a collar by the set-screw shown, and this collar is clutch shaped on its back face, engaging a similar clutch face on the shoulder of the arbor, the object of this arrangement being as follows. Suppose it is required to cut a thread a certain distance, as say,3⁄4inch, along a stud, and that the depth of the clutch is1⁄4inch. Suppose that when the turret is fed forward sufficiently the thread is cut half an inch along the work at the moment that the turret meets its stop and comes to rest, then the die will continue to feed forward one-quarter of an inch, moving along the body or stem of the holder until its clutch face disengages, when the die will revolve with the work.
Fig. 717Fig. 717.
Fig. 717.
Fig. 717represents a cutting-off tool and holder for a screw machine. The tool fits into a dovetail groove in the split end of the holder, and is ground taper in thickness to give the necessary clearance on the sides. It is held by the screw shown, which closes the split and grips the dovetail; obviously the top face only is ground to resharpen it.
Fig. 718Fig. 718.
Fig. 718.
Fig. 718represents a special lathe for wood work designed and constructed by Charles W. Wilder, of Fitchburg, Massachusetts. It is intended to produce small articles in large quantities, cutting them to duplicate form and size without any further measurements than those necessary to set the tools in their proper respective positions. It is employed mainly for such work as druggists’ boxes, tool handles, straight spokes for toy vehicles, piano pins, balls, rings, and similar work.
Its movements are such that the tools are guided by stops determining the length and the diameter of the work so as to make it exactly uniform, while the form of the cutting tools determines the form of the work, which must therefore be uniform.
The lathe may be described as one having a carriage rest spanning the bed of the lathe, which rest holds the work axially true with the lathe centres without the aid of the dead centre, while it at the same time trues the end of the work and leaves it free to be operated upon by other tools, which, after once beingset and adjusted, shape any number of pieces of work to exact and uniform diameter and shape.
Fig. 719Fig. 719.
Fig. 719.
Fig. 720Fig. 720.
Fig. 720.
The manner in which this is accomplished is as follows:Fig. 718is a general external view of the lathe;Fig. 719is an end elevation view of the rest from the cone spindle end, andFig. 720is an end view of the rest viewed from the tailstock end of the lathe.ais a ring fastened in the restrby the set-screwb. The mouthcof the ring which first meets the work is coned, or beveled, as shown, and an opening on one side of the ring admits a cutting toolt. Now the work is placed one end in the cone driving chuck on the lathe spindle, and the other end in the cone or mouthc,Fig. 719, being kept up to the driving chuck by the end pressure ofc. As the work rotates, the tooltcuts it to the diameterdof the ring bore, the carriage or restrtraversing along the lathe bed as fast as tool cuts; hence the boredserves as a guide to hold the work and make it run true, this bore being axially true with the lathe centres. The cone surface ofcthus operates the same as the sole of an ordinary carpenter’s plane, the tooltcutting more or less rapidly according as its cutting edge is set to project more or less in advance of the surface of the cone or recessc. This admits of the tool cutting at a rate of feed that may best suit the diameter of the work and the nature of the wood. The toolt, is operated laterally to increase or diminish the rate of feed by the screwe, which also serves as a pivot, so that by operating the thumb-screwf, the tool point may be adjusted for distance from the centre of the bored, or in other words the diameter to which the tooltwill turn the work is adjusted by the thumb-screwf.gis the head of the pivot screw that the swing tool holderhworks upon, and this swing motion carries the forming tool or cutterx, which shapes the work to the required form.iis a shaft upon which a lever, carrying the tool holderj, works, the latter carrying the severing toolk, which severs the finished work from the stick of wood from which the work is made.
The tool holdershandjare connected by means of the armslandmto the studo, fast in wheelp, operated by a knee leverq, which is pivoted atstou, which is fast to one of the gibs that hold the carriage to the latheVs. The knee leverqis connected to the wheelpby a raw-hide strap, or beltv, so that the operator, by pressing his knee upon the end of the leverq, causes the wheelp, to partly rotate, carryingowith it (obeing fast inp), and gives a forward radial motion to tool holderhand cutterx, causing the latter to enter the work until such time as the studoand the screw studware in line, horizontally with the centre of the wheelp, after which tool holderhwill move back, while the severing toolk(which has a continuous upward or vertical movement) is cutting off the finished work, which has been formed to shape, and reduced to the required diameter by the forward movement of the tool or cutterx. The object of the backward or retiring motion ofhis to relieve the shaping toolxfrom contact with the work, whilekcuts it off, or otherwise the work might meetxwhen cut off, and receive damage from contact with it. The studw, connecting tool holderhwith the wheelp, is threaded with a right and left-hand screw, by operating which the toolxmay be operated to reduce the work to any required diameter.
The rest or carriagertraverses along the lathe shears or bedz, carrying with it all the levers and tools, so far described.
The tailstock, or back head, carries a tool holder in the rear of the spindle, in which fits also a drill bit or other cutting tool. The method of traversing and operating the carriagerand the back head is as follows:
At the back of the bed or shears is a table, shown att, inFig. 718. Upon this table is a stand to which is pivoted the end of a lever, as is shown at 1 in figure. This lever has a joint at 2, and is connected to the tailstock spindle at a joint marked 3. It is obvious that by operating the lever laterally, joint 2 will double, and the tail spindle will be moved along the bed. If the tail spindle is not locked it will simply feed through the tailstock andthe tool in the spindle will operate, but if it is locked (by the ordinary screw shown), then the handle will slide the whole tailstock and the tool in the holder at the back of the tail spindle may operate.
At 4 is an adjusting screw, which, by coming into contact with the carriagercauses it also to traverse, which it will do until it meets against a screw on the other side, marked 5, inFig. 718, which, standing farther out than the chuck prevents the cutting tool from meeting the chuck.
The movement of the carriage continues until the stop-gauge 6 meets the end of the work, hence the length of the work is from the cutting-off tool to the face of stop 6. The adjustment for the length of the work is made by means of screw 4, which will slide the carriager, as soon as it meets it, independent of what distance the stop 6 may be from the work end. The tailstock carries two tool holders, similar to those on an ordinary lathe. When the cutting tools are used to cut completely over the end of the work, as in ball turning or a round ended handle, the stop 6 is not used, the tool which rounds the end acting as a stop of itself.
When bits are used they are held in the tail spindle and are made of a proper length to give the required depth of hole, or sometimes the face of the bit-holder may be used as a stop.
When the tools, cutters, and belts are all properly adjusted in position to cut to the required respective diameters or lengths the operator has simply to place a stick of wood in the lathe and operate the respective handles or levers in their proper consecutive order, and the work will be finished and cut off, the operation being repeated until the stick is used up, when a new one may be inserted, and so on.
Fig. 721Fig. 721.
Fig. 721.
Lathes for Irregular Forms.—In lathes for irregular forms (which are chiefly applied to wood and very rarely to metal turning), the work is performed by rotary cutting tools carried in a rapidly rotating head. The work itself is rotated slowly, and the carriage or frame carrying the cutting tools is caused to follow the outline of the pattern orformerat every point in its circumference as well as in its length. The principle of action by means of which these ends are attained is represented inFig. 721, in whichsrepresents a slide which carries the sliding head, affording journal bearing to the rotating headh, driven by the belte, and carrying the cutters, and also the wheelw.frepresents the pattern or former, andba piece of wood requiring to be turned to the same form as that off. Suppose then thatfbe slowly rotated byaandc, receiving rotary motion froma(through the medium ofd), then the rotations ofcwill equal those off, because the diameter ofais equal to that ofc. The diameter of the circle described by the cutters athis also equal to the diameter ofw, hence the motion of the extremities of the cutters is precisely the same as that of the circumference ofw, and aswreceives its motion fromfit is obvious that the cutters will reducegto the same form and size asf, and if the head be traversed in the same direction as the axis off, then the diameter and form ofbwill be made to correspond to that offat every corresponding point throughout its length. Contact betweenwandfis maintained by means of a weight or spring, the rotation offbeing sufficiently slow to insure its being continuous, while the necessary rapidity of cutting speed for the tools is attained by rotatinghat the required speed of rotation.
This class of lathe is termed the “Blanchard” lathe from the name of the inventor, or “Lathe for irregular forms,” from the chief characteristic of the work, but is sometimes designated from the special article it is intended to turn, as “The Shoe-last lathe,” “Axe-handle lathe,” “Spoke lathe,” &c., &c.
Fig. 722Fig. 722.
Fig. 722.
LetFig. 722represent a lathe of this kind provided with a frameaaffording journal bearing to the shaft of the drumb, which is driven by the pulleysc. Leterepresent a pulley receiving motion frombby the beltd. The cutting tools are carried by the headfwhich is rotated by pulleye. Let the carriage or frame carrying the shaft ofecarry a dull pointed tracer, with continuous contact with theformerhby means of a weight or spring, the carriage being so connected to the waynon which it traverses that it is capable of rocking motion, and ifhbe rotated the carriage will, by reason of the tracing point, have a motion (at a right angle to the axis ofh) that will be governed by the shape ofh; hence sincegrotates equally withh, the form of the blank workgwill be similar to that ofh, but modified by reason of the tracing point being at a greater distance thanffrom the centre of rocking motion.
All that is necessary to render this motion positive throughout the lengths ofgandhis to connect them together by gears ofequal diameter, and traverse the carriage alongnfor the full length of the pieces. But the effect will be precisely the same if the frame carryinggandhbe pivoted below, capable of a rocking motion, andhbe kept against the tracing point by means of a spring or weight, in which case the carriage may travel in a straight line uponnand without any rocking motion. This would permit of the carriage operating in a slide way onnenabling it to traverse more steadily.
To maintain continuous contact between the tracing point and theformerh, the rotations ofhare slow, the necessary rapidity of tool cutting action being obtained by means of the rapid rotation of the head and cuttersf.
Since motion from the line shaft to the machine is communicated atcit is obvious that the gears or devices for giving motion tohandgmay be conveniently derived from the shaft carryingcandb, for which purpose it extends beyond the frame at one end as shown. Lathes of this kind are made in various forms, but the principles of action in all are based upon the principles above described.
Fig. 723Fig. 723.
Fig. 723.
Back Knife Gauge Lathe.—This lathe,Fig. 723, has a carriage similar to that described with reference toFig. 718, and carries similar tools upon the tailstock. It is further provided, however, with a self-acting feed traverse to the carriage, and by means of a rope and a weight, with a rapid carriage feed back or from left to right on the bed, and also with a knife at the back. This knife stands, as seen in the engraving, at an angle, and is carried (by means of an arm at each end) on a pivoted shaft that can be revolved by the vertical handle shown. The purpose of this knife is first to shape the work and then to steady and polish the wood or work. Obviously when the knife is brought over upon the work its cutting edge meets it at an angle and cuts it to size and to shape; the surface behind the cutting edge having no clearance rubs against the work, thus steadying it while polishing it at the same time. These lathes are used for turning the parts of chairs, balusters, and other parts of household furniture, the beads or other curves or members being produced on the work by suitably shaped knives, which obviously cut the work to equal shape and length as well as diameter, and it is from this qualification that the term “gauge” is applied to it.
Fig. 724Fig. 724.
Fig. 724.
Fig. 724represents the Niles Tool Works special pulley turning lathe, in which motion from the cone spindle to the live spindle is conveyed by means of a worm on the cone spindle and a worm-wheel on the live spindle. Two compound slide rests are provided, the tool on the rear one being turned upside down as shown. These rests may be operated singly or simultaneously, and by hand or by a self-acting motion provided as follows:—A screw running parallel to the cone spindle is driven by suitable gearing from the cone spindle. At each end of this screw it gears into a worm-wheel having journal bearing on the end of the slide rest feed screw as shown. By a small hand wheel on the end of the slide rest feed screw the worm-wheel may be caused to impart motion to the feed screw by friction causing the slide rest to feed. But releasing this hand wheel or circular nut releases its grip upon the feed screw, and permits of its being operated by the handle provided at the other end. The rail carrying the slide rest is adjustable in and out to suit varying diameters of pulleys, being secured in its adjusted position by the bolts shown.
The cut is put on by means of the upper part of the compound rest. To turn a crowning pulley the rails carrying the slide rests are set at an angle, the graduations shown on the edge of the ways to which they are bolted being to determine the degree of angle. When the pulley surface of the pulley is to be “straight” both tools may commence to operate on one edge of the pulley surface, the advance tool taking a roughing and the follower tool a finishing cut; but for crowning pulleys the tools may start from opposite edges of the pulley, the cuts meeting at the middle of the face; hence the angles at which the respective rails are set will be in opposite directions.
The pulleys to be turned are placed upon mandrels and driven by two arms engaging opposite arms of the pulley. To drive both arms with an equal pressure, as is necessary to produce work cylindrically true, an equalizing driver on Clements’ principle (which is explained inFig. 756, and its accompanying remarks) is employed.
For driving the pulleys to polish them after they are turned the cone spindle is hollow at the rear end and receives a mandrel. The high speed at which the cone spindle runs renders this possible, which would not be the case if wheels and pinions, instead of worm-gear, were employed to communicate motion from the cone to the live spindle. A wheel shown in position for polishing is exhibited in the cut, the pivoted arm in front affording a rest for the polishing stick or lever.
Boring and Turning Mills.—The boring and turning mill patented in England by Bodmer in 1839, has developed into its present improved form in the United States, being but little known in other countries. It possesses great advantages over the lathe for some kinds of turning and boring, as wheels, pulleys, &c.
The principal advantages of its form of constructionare:—
1st. That its work table is supported by the bed at its perimeter as well as at its centre, whereas in a lathe the weight of thechuck plate as well as that of the work overhangs a journal of comparatively small diameter, and is therefore more subject to spring or deflection and vibration.
2nd. It will carry two slide rests more readily adjustable to an angle, and more readily operated simultaneously, than a lathe slide rest.
3rd. It is much more easy to chuck work on a boring mill table than on a lathe, because on the former the work is more readily placed upon the table, and rests upon the table, so that in wedging up or setting any part of the circumference of the work to the work table, there is no liability to move the work beneath the other holding plates; whereas in a lathe the work standing vertical is apt when moving or setting one part to become unset at other points, and furthermore requires to be held and steadied while first being gripped by the chucking dogs, plates, or other holding devices.
Figs. 725,726,727,728, and729represent the design of the Niles Tool Works (of Hamilton, Ohio), boring and turning mill. In this design provision is made to raise the table so that it takes its bearing at the centre spindle only when used upon small work where a quick speed of rotation is necessary, or it may be lowered so as to take its circumferential bearing for large heavy work where slower speeds and greater pressure are to be sustained.
The bearing surfaces are, in either case, protected from dust, &c., and provided with ample means of lubrication. Each tool bar is so balanced that the strain due to the balancing weights is in a line parallel to the bar axis in whatever position and at whatever angle to the work table the bar may be set. This prevents the friction that is induced between the bar and its bearings when the balancing strain is at an angle to the bar axis, and consequently pulls the bar to one side of or in a line to twist the bar. The bar is therefore more easily operated, and the feed gear is therefore correspondingly relieved of strain and wear.
Fig. 725Fig. 725.
Fig. 725.
The general construction of the machine is shown inFig. 725. It consists of a base or bed, affording journal bearing and support to a horizontal work table, rotated by devices carried upon the bed. To each side of the bed are attached uprights or standards, forming a rigid support to a cross slide or rail for the two sliding heads carrying the tool bars.
Largeimage(76 kB).Fig. 726Fig. 726.
Largeimage(76 kB).
Fig. 726.
Largeimage(84 kB).Fig. 727Fig. 727.
Largeimage(84 kB).
Fig. 727.
The various motions of the machine are as follows: There are 16 speeds of work table, 8 with the single, and the same with the back gear. The cross slide is capable of being raised or lowered, to suit the height of the work, by an automatic motion. Both tool rests are capable of hand or automatic feed motion at various rates of speed, in a line parallel to the surface of the work table. Both are also capable of automatic or hand feed motion, either vertically or at any required angle to the work table, and have a quick return motion for raising them, while each may be firmly locked while taking radial or surfacing cuts, thus preventing spring or vibration to the tool bar. In addition to this, however, there is provided, when required, a tailstock, carrying a dead centre after the manner of a lathe, so that the work may be steadied from above as well as by the work table. InFigs. 726and727are shown the devices for raising the work table and those for actuating the feed screws and the feed rod; thus operating the sliding heads horizontally and the tool bars vertically.ais the base or bed supporting the work carrying tableb′, and affording its spindle journal bearing atd′. A step within and at the foot ofd′rests upon the wedgef′so that when the wedge is caused to pass withind′it lifts the step, which in turn lifts the table spindle, and hence the table, sufficiently to relieve its contact with the outer diameter of the bed.f′is operated as follows: The leverg′is pivoted ate′and carries at its upper end a nuth′, operated by a screw on the end of the bolti′; hence rotatingi′, operates wedgef′.
For operating the automatic feed motions,fis a disc upon a shaft that is rotated by suitable gears beneath the work table;gis a disc composed of two plates, having a leather disc between them, the perimeter of the disc having sufficient frictional contact withfto causegto rotate whenfdoes so:gdrives the vertical spindlei, which has a worm atj′driving a worm-wheel which rotates the gears upon the feed spindlesv,f,w, in the figures;frotates in a continuous direction, but the spindleiis caused to rotate in either direction, according to whether it has contact with the top or bottom of the face off, it being obvious that the motion offabove its centre is in the opposite direction to that below its centre of rotation. The means of raising and loweringgto effect this reversal of rotative direction is as follows: It is carried on a sleeveg′which is provided with a rack operated by a pinion that is rotated by means of hand wheelh; hence, operatinghraises or lowersg′, and thereforeg;h′is a hand wheel for locking the pinion, and hence detaining the rack (and thereforeg) in its adjusted position. This design is an excellent example of advanced American practice for obtaining a variable rate of feed motion in either direction, it being obvious thatg, being driven by the radial face off, its speed of rotation will be greater according as it is nearer to the perimeter offand less as it approaches the centre off, at which point the rotary motion ofgwould cease. Here, then, we have a simple device, by means of which the direction and rate of feed may be governed at will with the mechanism under continuous motion, and conveniently situated for the operator, without his requiring to move from the position he naturally occupies when working the machine.
The means of raising or lowering the height of the railron the side standardszare as follows:kis a pulley driven by belt from the countershaft and operating pinionl, which operates pinionn, drivingm.ois a gear on the shaft driving the pinionsp,p, which operate the gearsq,q, on the vertical screws which engage with nuts attached tor;mandnare carried on a bell-crankrpivoted on the shaft of pulleyk. Pinionnis always in gear with pinionl, and pinionmis always in gear with pinionn(and not with pinionl). With the bell-crank in one position, motion passes fromltonand too; but with it in the other position, motion passes fromlton, thence tom, and from it too. The motion ofm, therefore, is always in a direction opposite to that ofn; henceo, and gearspandq, may be operated in either direction by regulating which of the two gearsn,mshall driveo, and this is accomplished as follows: The bell-crankris connected by an arm to rods, and the latter is connected by a strap to an eccentrict, operated by the handle shown. When this handle stands horizontally, bothmandnare disengaged from piniono; but if the handle be raised, rodsis raised, andmis brought into gear witho. If, however, it be lowered from the horizontal position,nis brought into gear witho, andmbecomes an idle wheel.
Fig. 728Fig. 728.
Fig. 728.
There are two feed screws—one for operating each boring bar-head, and a spindle for operating the vertical feeds of the bars in the sliding heads.Fig. 728shows the arrangement for engaging and disengaging the feed nuts of these heads.ais the slide that traverses the rail. It carries a nut made in two halves,nandn′, which are carried in a guide or slide-way, and which open from or close upon the screwfwhen the handleois operated in the necessary direction. Each half of the nut is provided with a pin projecting into eccentric slotsxin the face of a pivoted plate (shown dotted in), to which the handleois attached.w,wrepresent bearings for the vertical feedspindlewinFig. 726.ais the annular groove for the boltsbinFig. 729.
For a quick hand traverse for the head the ratchet,pis provided, operating a pinions, which engages with a rackt, running along the underneath side of the cross-railr. To adjust the fit ofato the rail the gibsyandy′and the wedgexare employed.
Fig. 729Fig. 729.
Fig. 729.
Fig. 729represents the automatic feed motion within the head for operating the tool bars vertically.ris the cross rail on which slidesacarryingb, and permitting it to swivel at any angle by means of boltsb, whose heads pass within an annular groove,aina. Inbis carried the boring barg, having the rack shown.pis a pinion to operate the rack.wis the feed-rod driving the wormh, which drives the worm-wheeli. This worm-wheel is provided with a coned recess, into which the friction platecfits, so that when the two are forced together rotary motion fromiis communicated toc, and thence toc′(which is a sleeve uponc), where it drives pinionpby means of pinp′.irotates upon and is supported by the studj, which is threaded intoc2(the latter being also a continuation ofc); hence when hand-wheelkis operated in one direction,c2acting as a nut causesjto clampitoc, and the tool bar to therefore feed. Conversely, whenkis operated in the opposite direction,iis released fromc, and may, therefore, rotate whilecremains at rest. For feeding the tool bargby hand, or for moving it rapidly, the hand-wheelmis provided, being fast to the sleeve at its sectionc2, and, therefore, capable of rotating pinionp.daffords journal bearing tocat its sectionc′. The chain from the weights which counterbalance the barsgpass over sheaves which are fixed to the piecebin which the bar slides, so that they occupy the same position with relation to the axis of the bar at whatever angle the latter may be set, and thus the counterbalancing weight is delivered upon the bar in a line parallel to its axis. As an example of the efficiency of the machine, it may be mentioned that at the Buckeye Engine Co.’s Works, at Salem, Ohio, a pulley 12 feet in diameter, weighing 8860 pounds, and having a 27-inch face, was bored and turned on one of these machines in 17 hours, taking three cuts across the face, turning the edge of the rim facing off the hub and recessing the bore in the middle of its length for a distance of several inches, the bore being in all 18 inches deep. The machine is made in different sizes, and with some slight variations in each, but the main features of the design, as clearly shown in our engravings, are common to all sizes.
Fig. 730represents a lathe for turning chilled rolls such as are used for paper calendering machines, and is constructed by the J. Morton Poole Company of Wilmington, Delaware.