Modern Machine-Shop Practice Part 210

Fig. 3098 represents a circular saw machine, constructed by the Egan Company, in which the table is carried on a vertical slide, and may be raised or lowered by means of the hand-wheel, bevel gears, and screw shown, and may be set at any required angle to the saw for cutting bevels.

The saw arbor or mandrel is carried by the main frame, and is therefore rigidly held.

The fences can be used on either side of the saw, which is very convenient when the table sets out of the level.

BEVEL SAWING MACHINE OR COMBINATION MITRE SAWING MACHINE.

In this machine, which is shown in Figs. 3099, 3100, and 3101, the construction permits of the saw being set so as to revolve at other than a right angle to the work table, which is rigidly secured to the frame of the machine.

This machine is constructed by J. S. Graham & Company, and its action may be understood from the following:

Fig. 3099 is a general view, while Figs. 3100 and 3101, are sectional views of the machine.

The table is firmly bolted to the frame, and is fitted with the necessary groove slides and fences for rip sawing and cross cutting. It is also provided with a removable piece, which allows the use of wabbling saws, dado heads, etc.

[Ill.u.s.tration: Fig. 3099.]

[Ill.u.s.tration: Fig. 3100.]

The sides of this machine A, A, Fig. 3099, are cast with an extension for countershaft. Referring now to Figs. 3100 and 3101, the upright piece I, I, with arms B B, and G, G, is bolted to the frame as shown.

The arbor frame M, M, is gibbed to T, T, by the circular piece U, and is moved to any angle by the hand wheel Z, which operates the worm W, which in turn moves the arbor frame M, M. This arrangement does not require any locking device to hold the saw in position. As the centre upon which the arbor swings is in the intersection of the planes of the saw and table top, the opening in the table needs not be larger than for the ordinary saw. When cutting a mitre the saw takes the position J, Fig.

3101. When cutting at a right angle the saw takes the position J' and the arbor takes the position P' N'.

[Ill.u.s.tration: Fig. 3101.]

The saw arbor can be raised and lowered by the use of the hand wheel which operates the screw _b_ (Fig. 3100.)

There is an accurate index located in front of the machine in sight of the operator, marked from 0 to 45.

The iron table is of one piece 4 feet by 3 feet and fitted with the necessary groove slides for ripping and cross cutting gauges. It is also provided with removable piece E, Fig. 3101, allowing the use of dado head, etc. The table is provided with a bevel slitting gauge S', and cross cut or mitering gauge X', Fig. 3099, which in connection with the angular adjustment of the saw enables the operator to get every conceivable plain or double mitre ever required. The pulleys A', B', are made wide to allow the belt to travel as the saw is inclined. The pulley B' takes up the slack of the belt. The countershaft and tightener are a part of the machine and can be run wherever a belt can be brought to them.

ROLL FEED CIRCULAR SAWS.

Figs. from 3102 to 3105 represent a roll feed circular saw, by J.

Richards.

Fig. 3102 is a side elevation, Fig. 3103 a plan, and Fig. 3104 a cross-sectional view through the rolls.

In Fig. 3102, P is the saw-driving pulley, T a stand for carrying the saw guides _a_, _b_, _c_, _d_, which are adjustable for height by means of the arm whose set screw is shown at U; at W is the spreader for opening out the board after it has been cut by the saw, and thus prevent its binding against the saw and heating it.

The construction of the feed motion is shown in Figs. 3103, 3104, and 3105.

On the saw arbor is the feed cone C, Fig. 3103 having four steps so as to give four rates of feed. This cone connects by belt to feed cone D, whose shaft drives feed pulley E, which drives F by belt connection. F drives two worms shown by dotted lines at H and I, and these drive the worm wheels which drive the feed rolls, one of these worm wheels being shown at K, in the side view, Fig. 3102.

The feed roll L (Fig. 3103) is supplemented by a fence or gauge face P, which guides the work closer up to the saw than would be possible with a roll, and a supplemental roll is provided at M, thus affording a guiding surface for the work from M to the end of P. The stand for guide roll L fits in a slideway, and is adjustable along it by means of the screw S.

Similarly the stand for roll N is fed along its slideway by screw R.

There are three separate sets of saw guides, all of which are shown in the plan view Fig. 3103, and of these the top ones, _a_, _b_, _c_, _d_, _e_, _f_, _g_, and _h_ are adjustable by nuts. The front ones, _l_, _m_, _n_, _o_, _p_, _q_, and the back ones, _i_, _j_, _k_, and _r_, _s_, _t_, are adjustable by means of the wedges _w_. At Z is a wedge for adjusting the spreader W so as to keep it close to the saw whatever the diameter of the latter may be.

[Ill.u.s.tration: Fig. 3102.]

[Ill.u.s.tration: Fig. 3103.]

Fig. 3105 is an end view of the machine showing the feed worms H and I, and the belt tightener V, which is carried on the arm _u_ on whose shaft is the weight _y_, attached to which is the handle X.

[Ill.u.s.tration: Fig. 3104.]

[Ill.u.s.tration: Fig. 3105.]

SEGMENTAL CIRCULAR SAWS.

[Ill.u.s.tration: Fig. 3106.]

A segmental circular saw is one in which the saw is composed of segments secured by screws to a disc, the construction being such as shown in Fig. 3106, in which A is the saw arbor, D the disc, and E, F, G, H, I, J, etc., the segments.

The segments are made of varying thicknesses at the cutting edge, and are tapered for a distance for from 6 to 8 inches inwards from the teeth points. Thus in the figure there is shown at P an edge view of a segment, from _a_ to _b_ being parallel, and from _b_ to _c_ being ground off taper.

The segments are held to the disc by the two sets of screws, R, S, and are further secured at their edges by pieces of copper, as shown at W.

Between the edges of the segments there is left a s.p.a.ce or opening of about 1/16 inch, which is necessary to insure that the segments shall not bind together edgeways, as that might prevent their seating fairly against the face of the disc D.

The seats for these pieces of copper are shaped as shown in the face views at W, and in the edge views at W', the mouth of the slot being widened on each side, so that riveting up the pieces of copper will prevent the segments from moving sideways.

In fitting in these pieces of copper, it is essential to take care that they do not completely fill the slots, but leave a small opening at each end of the slot, as at _f_ and _g_ in the figure, and in order to do this the copper must be left about 1/8 inch narrower than the width of the slot.

If the copper is, in riveting up, brought to bear against the end of the slot, it will twist the segments out of line one with the other, causing the saw to drag, cut roughly and produce bad work.

[Ill.u.s.tration: Fig. 3107.]

[Ill.u.s.tration: Fig. 3108.]

Figs. 3107 and 3108 represent portions of segmental saws for cutting veneering. In some of these saws the screw holes are so arranged that the segments can be moved out to maintain the diameter of the saw as it wears.

GANG EDGING MACHINES.

For dressing the edges of planks parallel and to width what are called gang edgers or gang edging machines are employed.

A gang edger consists of an arbor driving two or more circular saws, through which the boards to be edged are fed. Means are provided whereby the distance apart of the saws may be rapidly adjusted while the saws are in motion, so that if a board will not true up to a given width, the saws may be set to cut it to a less one without delay.

[Ill.u.s.tration: Fig. 3109.]

Fig. 3109 represents a self-feeding gang edger, constructed by J. A. Fay & Company, and in which the left-hand saw may be fixed at any required position on the left-hand half of the saw arbor, while the two right-hand ones may be adjusted independently along the arbor, while the machine is running.

At the back of the saw is a feed roll, and above it a pressure roll, whose pressure may be regulated by means of the weight and bar shown at the back of the machine. The object of placing the feed and pressure rolls at the back of the saws, is, that if a board is found to be too narrow for the adjustment of the saws, it may be withdrawn without stopping or reversing the machine, and the saws may be drawn together sufficiently to suit the case.

Fig. 3110 is a plan and Fig. 3111 an edge view of the work table, and show the means of adjusting the saws. A is the saw arbor, and 1, 2, 3, the circular saws. Saw 1 is carried by the sleeve B, which is secured in its adjusted position by the set screw C.