The feed rolls are carried in slides which are operated in slideways by means of screws, and the two back rolls, or those nearest to the column are maintained vertical. The two front ones, however, are provided with means by which they may adjust themselves to bear along the full depth of the work, notwithstanding that it may be taper. The construction by means of which this is accomplished is shown in Figs. 3136 and 3137, in which a is front and b a back feed roll. The bearings of feed roll a abut against rubber cushions c, c, whose amount of compression is regulated by the set screws d, d.

The construction of the saw guides is shown in Fig. 3138, which is a plan view partly in section. s s are hardened steel plates set up to the saw by means of studs whose nuts are shown at n n. w is a friction wheel which supports the saw against the thrust caused by the work feeding to the saw. The adjustment of the wheel w to the saw is obtained by means of the wheel h.

The hand wheel h operates the screw r r, that adjusts the wheel w to the saw, the wheel j serving to lock the screw in its adjusted position.

Fig. 3139 represents Worssam’s band saw machine, in which the standard may be set at any required angle for cutting bevels.

When the work is heavy and not easily handled it is preferable to set the standard and saw at the required angle, rather than to set the table at an angle and have the saw remain vertical. In Worssam’s machine this is accomplished as follows:

a is the main frame carrying the work table t, and having circular guideways b, b′, which carry the standard c having guide c′ for working in the circular guideways b, b′.

The saw-driving wheel d, is carried in bearings provided in c, and, therefore moves when the standard c is moved.

At the upper end of c, is the slide e, which carries the bearing for the upper wheel f, this slide being adjusted to regulate the saw tension by the hand wheel o, whose screw threads into a nut in the slide e. h carries the front guide g, for the saw, the back guide g′ being carried by a bracket bolted to c. The back guide is fixed in position, but the front one is adjustable to suit the height of the work by raising or lowering it.

The means for setting the saw at the required angle to the work table are as follows:

At the back of the standard c is a rack j, whose pitch line is an arc of a circle of which the axis of the guideway c′ is the centre.

Into the rack j fits the worm wheel k, at the bottom of the shaft of which is a pair of bevel gear wheels l, which are operated by the hand wheel m.

A band saw machine constructed by Messrs. London, Berry & Orton, is shown by Figs. 3140, 3141 and 3142, in plate XXIII. The saw-driving wheel d, has wrought iron arms turned true and screwed into the wheel hub. The wooden segments have their grain lengthways of the rim, and between them are placed pieces of soft wood with the grain across the rim. This acts to keep the joints tight, notwithstanding the expansion and contraction of the wood.

The upper wheel is adjusted for straining the saw, and for leading the saw true, by the following construction. It is carried in a U-shaped frame f, which is pivoted at y to a slide that is gibbed to the main frame, and by operating the screw shown at x, the frame f is set to the required level.

To regulate the tension of the saw, the hand wheel k is operated, which drives the pair of bevel gears j and i, the latter of which operates the threaded shaft h, whose upper end g connects with the slide which carries f. Within g is a spring to act as a cushion to the slide, and thus prevent saw breakage should a chip pass between the saw and its driving wheel.

The saw guide frame is secured to the main frame at m′, m′. Upon the face of m, is a slideway for the saw guide arm n, which may thus be adjusted as closely to the upper face of the work as possible.

The weight of arm n is counterbalanced by a rope passing over the pulley v, and supporting the counterbalance weight w. The feed motion is constructed as follows:

On the same shaft as the main fast and loose pulleys a, b, is the feed pulley l, which by belt connection drives pulley m, which is on the shaft w, upon which is a friction disc n, by means of which the rate of feed is regulated. The feed disc n drives the wheel o; the degree of contact between these two (n and o) is regulated by means of the weight t, on the lever u.

On the same shaft as the friction wheel o, is a pinion driving the gear x, which is on the same shaft as the pinion y, which drives the two gears y′ and y′′.

Referring now to Fig. 3142, gear y′ drives the pair of bevel gears z and z′, for the feed roll e, and the pair of bevel gears shown at z′′, the feed roll f. The gear y′′ drives similar gearing for the feed rolls e′ and f′, seen in the plan Fig. 3140.

Referring now to the plan Fig. 3140, and the side elevation, Fig. 3142, the feed roll f is carried in a frame g, which is fitted on the slideway d, d, and receives a screw i, upon which is a hand wheel h; at the back of this wheel is the lever j, which is weighted as shown, so that the force with which feed roll f grips the work is determined by the weighted lever j, and may be varied to suit the nature of the work by moving the weight along j.

The construction of the gear for feed roll f′ is similar, as may be seen in the plan Fig. 3140, f′ being in a slide g′, which has a screw i′, and hand wheel h′, a weighted lever corresponding to j acting against wheel h′. In proportion as f and f′ are opened out to admit thick stuff or work, the hand wheels h and h′, respectively are used to screw the screws i and i′ into their respective slides g and g′, and thus maintain the weighted levers in their requisite horizontal positions. The feed rolls e and e′ are carried in slides c and c′, and are adjusted to suit the thickness of the stuff or work by a hand gearing, which consists of the hand wheel a, seen in the plan and in the front elevation, Fig. 3141, which drives the pinions b and b′, which operate screws for the slides c and c′, the latter being a left hand screw. The front rolls e and e′ are therefore held in a fixed position, whereas the back ones f and f′ may open out under the pressure of the weighted levers j, and thus accommodate any variation in the thickness of the work.

The rate of feed is varied to suit the nature of the work by the following construction: The friction wheel o and the hand wheel r are connected by a yoke q, Fig. 3142, at the ends of which are the joints p, q, seen in the plan, Fig. 3140. Hand wheel r is threaded to receive the screw s, and it follows that by revolving r, the friction wheel o may be moved towards the centre of the friction disc n, which would reduce the velocity with which n would drive o, and therefore reduce the rate of feed. If the friction wheel o be moved from the position it occupies in the plan Fig. 3140, to any point on the other side of the centre of the friction disc n, the direction of feed motion would be reversed.

A band saw machine for the conversion of logs into timber, and constructed by Messrs. London, Berry & Orton, is shown in Fig. 3143. The logs are fixed to the carriage by dogs and the carriage traverses the log to the feed.

Reciprocating Cross Cutting Saw For Logs.—The machine shown in Figs. 3144 and 3145 is designed for the purpose of cutting heavy and long logs into convenient lengths preparatory to cutting the logs up in other machines, and it is usually therefore placed at the entrance to the mill, where it is of immediate service as the lumber comes into the building.

The machine here shown is intended for logs up to 36 inches in diameter, is simple in construction, requires very little foundation, is easy to handle, and occupies but very little room.

The saw is here fed mechanically to its cut, whereas in some machines it is fed by its own weight, and therefore requires great care to be taken, when the saw is finishing its cut, in order to prevent it from falling after it has passed through the log.

Fig. 3145 is a side elevation and Fig. 3144 a plan of the machine, in which a is the frame of the machine on which are the bearings for the shaft b carrying the fast pulley c, loose pulley d and fly-wheel e at one end, and at the other, a crank disc f, whose pin is shown at g. This drives the saw k through the medium of the connecting rod h.

The saw is fast at the butt end to along slide j, j, which works in a long guide formed on the face of the swinging frame l, which pivots at one end on the shaft b and at the other is carried by a slide p, on the vertical slideway m, and is fed down the same to give the saw its cut by the screw whose hand wheel is shown at n.

v is a second guide for the saw, and being connected to the slide feeds down with the saw until it meets the log.

A counterweight w balances the weight of the slides and saw, so that there being a pit beneath the balance weight the saw and its guides may be raised so that the saw stands out of the way when not in use. y is a dog for holding the log, which is also blocked by the wedges z z′.

The construction of the main bearing is shown in Fig. 3146, in which it is seen that the hub or boss of the loose pulley is much longer than that of the fast one, thus providing a large amount of bearing surface, which is advantageous because the belt will remain longer at the loose pulley than it will on the tight one. The sleeves or bushes in which the shaft runs afford a simple means of renewal to restore the fit when the shaft has worn loose in its bearings.

It is obvious that as the guide frame l is pivoted to the shaft b, it carries the end of the saw (as it is fed down) in an arc of a circle of which the axis of b is the centre, whereas the slideway m is straight, and slide p therefore moves in a straight line instead of in the required arc. Provision however is made to accommodate these two motions as follows:

Fig. 3147 is a sectional view of the slides on the slideway m and Fig. 3148 a plan of the same. The hand wheel n corresponds to n in Fig. 3145. Upon the vertical slideway (in Fig. 3145) of the standard fits the slide p, which has a horizontal slideway for the slide r, which is free to slide automatically, having no screw or other device to restrain it, save the guide frame l, and therefore as this frame is lowered to feed the saw the slide r moves automatically to accommodate the arc of a circle in which the guide moves on account of being pivoted at b.

The roughest shaped trunk may be easily fixed on the travelling table, and a thin saw may be used as it may be very tightly strained. This machine is used either for breaking down timber, or for converting it from the log to any desired thickness, the thickness of the boards being very readily and easily varied.

The machine consists essentially of a framework carrying either one or two very thin and tightly strained saws operating horizontally and cutting on both strokes, so that the feed is continuous, the construction being as follows:

Referring to Figs. 3149 and 3150, a is a base plate or bed carrying two uprights or standards b, b, having guideways c, c, for the cross-head d, which has slideways e, e′, for carrying the frame f, f, which carries the saw g, which is guided on each side of the work by the guides h, h′.

The construction of the saw is shown in Fig. 3151, and it is seen that for half its length, the teeth are formed to cut when the saw moves in one direction, while for the other half the teeth slope in the opposite direction, and are therefore arranged to cut when the saw is on the opposite or return stroke, and the construction whereby the saw is enabled to cut on both strokes is obtained as follows:

Referring to Fig. 3149, the two slides e, e′, on which the saw-carrying frame f f slides, are not in line or parallel one with the other, but each slide is at an angle of about 85 degrees to the line of feed, so that as frame f is reciprocated at each stroke, one end of the saw advances towards the cut, and the other recedes from it, thus causing the saw to cut first on one half and then on the other of its length, one half cutting on the forward, and the other on the return stroke.

The studs or saw-buckles for attaching the saw to the frame are shown in Fig. 3151, in place on the ends of the saw, the part i, that fits in the frame f, Fig. 3149, being squared so that the saw cannot be twisted in tightening up the nuts of the saw-buckle.

The belt works for driving the saw are arranged as follows: at t are the fast and loose pulleys for driving pulley r, the belt passing from t over two pulleys (shown dotted in, Fig. 3149), u, u′, whence it stretches to the crank driving pulley r, whose bearing is provided on the cross-head, so that the two move together when the cross-head is altered in height from the work-table or carriage, to accommodate different thicknesses or diameters of logs.

It is obvious that in proportion as the cross-head is set nearer to the carriage, the belt from t to u, u′ would become slack; provision is made however, to prevent this as follows:

Pulley u, is carried on a frame or swing lever x, to which is attached by rope v the weight w, which therefore regulates the tension of the belt.

The cross-head d may be raised or lowered by belt power or by hand, as occasion may require, the usual course being to move it to nearly the required position by belt power, and then complete the adjustment by hand, a graduated scale being provided as shown, whereby the rack can be set to cut the required thickness of plank without measuring the timber.

The belt motion for raising or lowering the cross-head is obtained by the pulleys at y, the wheel for the hand adjustment being shown at y′. In either case the bevel gear wheels z, z′ operate, respectively, a vertical screw engaging a nut on the cross-head.

The log feed is obtained by a motion separate from the return motion, there being three rates of feed and a quick return motion, the construction being as follows:

Referring to Figs. 3149 and 3150, a is a belt pulley fast on the crank shaft, and driving pulley b, which is also shown dotted in. Pulley b drives the vertical shaft c, on which is the cone pulley d, having three steps, and which drives (by means of belt d′) cone pulley e, on which is a worm f, driving the worm wheel g, which runs idle on its shaft unless engaged therewith by means of the clutch h. The shaft of worm wheel g is omitted in Fig. 3149, so as to leave the belt-shifting mechanism for pulleys q, q′ exposed to view. On this shaft however is a pinion driving the gear wheel k, on whose shaft is a pinion l, driving the gear m, which engages the rack n, on the under side of the carriage.

The clutch h is engaged by the lever i, to the upper arm of which is attached the rod j, j, from the lever p, hence operating p (which is done by hand), back and forth, throws clutch h into and out of gear with the worm wheel g, and puts the carriage feed on or throws it out, according to the direction in which p is moved.

The upper end of shaft c is carried in a bearing on the cross-head, and is provided with a featherway or spline, so that as the cross-head is raised or lowered the upper end of c passes through its upper bearing, and the pulley b travels with the cross-head. The three rates of carriage feed are obviously obtained by means of the three steps on the cone pulleys d and e.

We have now to explain the construction of the mechanism for traversing the table back, and giving it a quick return motion, or in other words a quicker motion on the back than on the feed traverse, and this is arranged as follows:

q, is a fast and q′, q′′, are loose pulleys, one driven by an open belt r, Fig. 3150, and the other by a crossed belt r′, from a countershaft. The belt-shifting forks are operated by lever s, whose upper end engages with the rod t, which is operated by the lever u.

The loose pulleys q′ and q′′ are twice as wide as the fast pulley q.

Now suppose that lever u is moved to the right, and the belt would be moved from the loose pulley q′′ to the fast pulley q, while the other belt would merely be moved or shifted from one to the other side of loose pulley q′.

Similarly if lever u, be moved to the left, the belt on the loose pulley q′ will be moved on to the fast pulley q, and the belt on pulley q′′ would simply be moved across the face of the pulley, and as the countershaft pulleys for the two pulleys are of different diameters, therefore two rates of motion are obtained.

The shaft v, on which pulley q is fast, drives the pinion l, which drives m, the latter gearing with the rack beneath the carriage.

The carriage is guided by the wheels z, which are secured to it, and run on the iron guideways z′, the flanges of the wheels preventing side play, and causing the carriage traverse to be in a straight line.

WOOD-PLANING MACHINES.

The simplest form of planing machine for wood work, is the hand planer or buzz planer, as it is termed, an example of this class of machine being shown in Fig. 3152, which has been designed and constructed by George Richards, for the use of pattern-makers.

In this example, however, the table is made in two sections, the front one of which is below the cutter edges to an amount equal to the depth of the cut, and the back one level with the cutter edge, when the latter is at its highest point in its path of revolution, the construction being shown in Fig. 3153, in which j, j, represents the top part of the main frame of the machine, c the cutter head, b the front or feed table, a the back or delivery table, and w a piece of work being fed in the direction of the arrow.

Upon the upper surface of the frame j, j, and on the feed side of the cutter head is the carriage g, to which are pivoted two links l, l, which support the feed table b. At d is a hand wheel whose screw has journal bearing in a lug from the table, while the screw threads into a nut provided in the carriage. Obviously then by operating the hand wheel d, carriage g is moved along the top of the frame j, and the height of table b is adjusted. Thus if the carriage g is traversed to the left, the link l would fall more nearly to a horizontal position, and table b would lower. Or if g were moved to the right, links l would stand more nearly vertical, and table b would be raised, it being understood that table b is not permitted to move endways. Similarly by means of hand wheel c, carriage h may be moved to adjust the height of table a.

By this construction, the work can bed fairly on the delivery side, as well as on the feeding side of the cutter head, which is not the case when a single table is used.

It is obvious that the work must be fed in opposition to the pressure of the cut, which endeavors to push the work back from the cutter, and this limits the size of work that the machine can operate upon.

The work can be fed easier however, with a cutter skewed or set out of line with the axis of the cutter head. Thus in Fig. 3154, is the common form of cutter head, carrying two knives placed diametrally opposite, so that the weight of one counterbalances that of the other, and the head will therefore run steadily and smoothly. The knives k, k′ are here set parallel with the axis of the cutter head, hence the whole length of the cutting edge meets the work at the same instant, and a certain amount of time must pass after one cutting edge has left the work before the other cutter edge meets it.

This is remedied by the construction of cutter head shown in Fig. 3155, in which three cutters are used, and each cutter is set askew, or out of parallel with the axis of cutter head, so that the knife begins to cut at one end, and the cutting action gradually extends to the other, hence the cutting action is more continuous and uniform, and better work is produced, while less power is required to drive and feed the machine.

Fig. 3156 shows a cutter head with two skew cutters.

The cutter head is provided with a cover or guard, which is arranged as follows: In the table is cut a groove or slideway, in which a slide fits, and to this is attached a thin sheet-iron guard. To the slide is attached a weight, which draws the guard back to the fence after the work has passed over the cutter head. By this means the guard covers all the knife edge that protrudes beyond the work, no matter what the width or thickness of the work may be; the guard can however be fixed in position when a number of pieces of the same size are to be planed.

The fence provides a guide surface for the work, and its face may be set at any required angle to the surface of the work table. Suppose, for example, that the sides or edges of a piece of work require to be at an angle of 100 degrees to the top and bottom surfaces, then the top surface may be planed first, and the fence being set at an angle of too degrees to the table surface, the top of the work may be pressed to the surface of the fence while fed across the cutter, and as a result, the side or edge will be planed at 100 degrees to the top.

ROLL FEED WOOD PLANING MACHINE.

Fig. 3157 represents a roll feed wood planing machine, designed and constructed by George Richards & Co., of Broadheath, near Manchester, England, the construction being more fully shown in the detailed figures following. The machine consists essentially of a framework, carrying a cutter head with two knives, and having a pair of feed rolls, in front and a pair behind it. The front pair feed the timber to the cutter head and the back pair deliver it from the cutter head.

Each pair of rolls is geared together, so that both the top and bottom rolls act to give a positive feed. Immediately in front of the cutter head and between it and the feed rolls (i. e. the front pair of rolls), is a pressure bar extending across the full width of the machine, and having at its lower extremity a steel spring which presses the work down to the table, and thus causes it to be planed of an equal thickness throughout its length. Immediately behind the cutter head and between it and the delivery rolls (i. e. the back pair of rolls), is a pressure bar that also extends across the machine and prevents the timber from rising up from the table after it has passed the cutters, all timber being found to have a tendency to rise after having been acted upon by the cutters. The arrangement of the feed rolls, delivery rolls and pressure bars is shown in Fig. 3158, in which t, t, t, represents three sections of the work table and w, w, a piece of work passing through the machine in the direction of the arrow. Feed roller f is fluted to increase its grip upon the work and insure a positive feed. The lower feed roller f′, and the lower delivery roller d′, are fixed in position, their upper surface projecting above the work table to about ¹⁄₁₀₀ inch. This is necessary to take the thrust of the upper rolls (f, d) and prevent them from forcing the work down upon the surface of the table with an undue amount of pressure, which would induce friction and consume an unnecessary amount of power in driving the rolls. The method of adjusting the lower rolls will be explained presently.

Between the cutter head c and the feed roll f is the pressure bar p, and behind the cutter head is the pressure bar b, both these bars being more clearly seen in Fig. 3159, in which the work w is shown entering the machine, and the lower rolls and work table are removed.

Pressure bar p has at its lower end a steel spring j, Fig. 3159, and is supported at each end by circular links y, projecting into grooves provided in the main frame of the machine, as shown in Figs. 3160 and 3161, in which c is the cutter spindle, y the circular link at the end of pressure bar p, and y the circular link at the end of pressure bar b, the two fitting into the one stepped groove.

In Fig. 3162, the work is shown passing beneath the two upper rollers, and the spring j (which extends the whole length of the pressure bar), is depressed from the weight of the bar. By this construction, the work is pressed to the table at a point as close as possible to the cutters. The pressure bar p cannot drop beyond a certain point, because of its tail piece y′, Fig. 3160, which rests on the top of the frame at y′′ when the bar p has fallen to its required limit.

The feed pressure bar p is bolted to its circular links, as shown in Fig. 3162, in which y is a part of the circular link which is bolted to the pressure bar p.

The delivery pressure bar b (Fig. 3160) is riveted to and forms part of its links y. It acts through the medium of spiral springs s, which are carried in cases or boxes s′, which overhang the end of the bar b. A set screw s′′ regulates the pressure of the spring, and a screw a (Fig. 3162) regulates the height of the pressure bar.

The adjustments of the feed and delivery rollers are made as follows:

The feed pressure is obtained through the medium of weights, shown at w, w′, in Fig. 3163, upon the bars a, a′, whose ends are pivoted to the lower ends of links m, n, the upper ends of which are pivoted to the side frame of the machine.