Chapter XXXV: Wood Working Machinery (4)

A machine constructed by J. J. Spilker, for cutting mitre joints by hand, is shown in Fig. 3211. The frame A carries a slideway for the slide to which the mitre cutting knife K is secured. The handle G operates a pinion gearing into a rack, which gives vertical motion to the slide and knife. At _c_ is a fence or gauge against which the work is rested, and which is capable of a horizontal motion, so as to bring the work more or less under the knife. For heavy work, the fence _c_ is set back, so that the first cut of the knife will leave the moulding, as shown at H, partly severed, and a second cut is necessary to sever it; for very fine work, a fine shaving may be taken off by a cut taken on the end of each piece separately, after the piece is severed. At D is a graduated scale or rule for cutting the work to exact dimensions, and as its lines are ruled parallel to the right hand edge of the knife K, the inside measurements of a mitre joint may be taken at the outer edge, and outside measurements at the inner end of each line, a set stop at E serving to gauge the pieces for length.

MOULDING OR FRIEZING MACHINES.

These are machines that cut mouldings on the edges of the work. The term friezing is applied by some, when the machine has but one cutter spindle, while by others these machines, whether having one or two spindles, are termed edge moulding machines. Still another term applied to this class of machine is that of variety moulders or variety moulding machines.

In machines of this class, it is of primary importance that lost motion or play in the bearings be avoided, because the cutter end of the spindle overhangs its bearings, and any side play of the spindle in its bearings is multiplied at the cutting edges of the cutters. Perfect lubrication of the spindle bearings, and ample bearing surface on the journals and bearings, are therefore of the first importance.

The work is rested on the upper surface of the table, and is fed to the cutters by hand.

Figs. 3212 to 3215 represent a machine by J. S. Graham. The frame B, B, Fig. 3213, of this machine is cast in one piece cored out, and the base is wide, so as to give necessary solidity. The hollow column is fitted with a door W, and shelves V, V, forming a very complete case for the reception of tools, cutters, etc. The spindle boxes and slides C are one casting. They are planed on centres and held in the frame B´, Fig. 3215, by large gibs L, and sliding surfaces shown in C´, Fig. 3214. They are adjustable vertically by hand wheels K, in front of frame in connection with nut O, as shown in Fig. 3214, and require no lock to hold them at the proper height.

The cap O´ (Fig. 3213) has an oil chamber J and wick which feeds the oil to the upper bearing. The lower box is fitted with a patent self-oiling and adjustable step shown at _a_, _b_, _c_. The cap _a_, upon which the spindle D rests, has a small opening in the centre. The circular block _b_, under it, also has a hole in the centre. The bolt _d_ has two holes in it, one horizontal and the other vertical.

The chamber surrounding this step and cup is filled with oil. The motion of the spindle D on the cap _a_ causes the oil to flow from the chamber through the openings to the spindle. Thus the oil is kept in constant circulation. The end of this spindle D is by this arrangement kept always lubricated.

The spindles D are of 1-7/8 hammered tool steel accurately turned and fitted in the boxes, which are of extra length, and lined with the best genuine Babbitt metal. They are 30" from centre to centre, and have independent screw tops, as shown at S, enabling the operator to use various sizes for large or small work, or clear the table of either spindle for special work.

H is the threaded part of the screw top, G is the nut, and F the fill-up collars.

The iron table A, A is 5 feet by 4 feet, planed and fitted with concentric rings E, E around the spindle, to suit the various sizes of heads and cutters. A heavy wooden table, made of narrow glued-up strips of hard wood, can be used if preferred.

This machine has been run up to 6,000 revolutions per minute, without perceptible jar, and cutter heads as large as 8" diameter may be used on it for heavy work.

Fig. 3216 represents an edge moulding machine by J. H. Blaisdell. In this machine the table is raised or lowered by the hand wheel upon the central column. The construction of the spindle and its bearings is shown in the sectional view, which also shows the square threaded screw by means of which the table is raised. The spindle has a coned hole for receiving the cutter sockets, which are therefore readily removable.

Figs. 3217 to 3220 represent examples of the shapes of cutters for use on edge moulding or friezing machines. Fig. 3217 represents a cutter for bevelling the edge of the work, the cutting edges being at A, B, or at C, D, according to the direction in which the cutter is revolved.

Fig. 3218 represents an ogee cutter, in position on the cutter spindle. As these cutters are made solid and accurately turned in the lathe, they are balanced so long as the cutting edges are kept diametrally opposite. The front faces only being ground to sharpen the cutting edges, the cutter always produces work of the same shape.

Fig. 3219 represents a cutter (in a chuck) for cutting a dove-tailed groove, and Fig. 3220 one for rounding an edge, it being obvious that a wide range of shapes may be given to such cutters, and that, as they may be sharpened on an emery wheel, they may be left comparatively hard, thus enhancing their durability.

To regulate the depth to which a cutter such as shown in Fig. 3220 will cut, a collar or washer is placed beneath it to act as a guide to the edge of the work.

Fig. 3221 represents a machine in which rotary cutters are used to produce all kinds of panel work, as well as edge moulding or friezing. In this case the cutter is above the table, the latter being adjustable for height to suit the thickness of the work. Examples of some of the work are shown at the foot of the machine.

WOOD BORING MACHINES.

The rapidity with which holes may be bored in wood enables the feed to be most expeditiously performed by hand or by foot motion. A foot motion leaves both the workman's hands free to adjust and change the work, and is therefore suitable for light work or work having holes of a moderate depth.

The work tables of wood boring machines are provided with suitable fences for adjusting the work in position, and in some cases with stops to adjust the depth of hole.

Any of the augers or bits that are used in boring by hand may be used in a boring machine, but it is obvious that, as the bit or auger is forced to its feed by hand or foot, and as its revolution is very rapid, the screw point, which is intended as an aid in feeding when the bit is used by hand, is not necessary. On this account most augers for use in machines are provided with triangular points instead of screw points.

In Fig. 3222 is shown a wood boring machine by J. A. Fay & Co. The table is gibbed to a vertical slide on the face of the column, and is adjustable for height by the hand wheel A, which, through the medium of its shaft and a pair of bevel gears, operates the elevating screw B. The spindle C feeds through its bearings, the supporting rod D being pivoted at its lower end to permit C to feed in a straight line vertically. The feeding is done by the treadle F, which operates the rod E.

The table may be set at an angle of 30 degrees from the horizontal position.

The weight W counterbalances the treadle and brings it to its highest position when the workman's foot pressure is removed.

The holes may all be gauged to an equal depth (when they are not to pass through the work) by so adjusting the height of the table that the hole is of the required depth when the treadle is depressed to its lowest point, or limit.

Fig. 3223 represents a horizontal boring machine such as used in furniture and piano factories. The spindle feeds through the driving cone, being operated by the treadle shown. The work table is adjustable for height by the hand wheel and elevating screw. The usual fences, stops, and clamping devices may be applied to the table, which is on compound slides to facilitate the adjustment of the work.

Fig. 3223_a_ shows a double spindle horizontal boring machine, in which the table and work are fed up to the boring tools by hand. The spindles are adjustable in their widths apart, and may also be set at an angle. The work table is adjustable for height, and the spindle carrying head is adjustable across the machine.

Fig. 3224 represents a machine by J. A. Fay & Co., for heavy work, rollers taking the place of the work table. The drill spindles are fed by hand from the stirrup handles shown, which are weighted to raise up the spindles as soon as they are released.

MORTISING MACHINES.

The mortising machine for wood work consists essentially of an ordinary auger, which bores the holes, and a chisel for cutting the corners so as to produce the square or rectangular mortise that is usually employed in wood work.

The chisel is reciprocated and its driving spindle is provided with means whereby the chisel may be reversed so as to cut on either the sides or the ends of the mortise. The chisel is fed gradually to its cut.

Fig. 3225 represents a mortising machine for the hubs of wheels.

The auger spindle is here fed vertically by a hand lever, the depth bored being regulated by a rod against which the hand lever comes when the hole is bored to the required depth.

Fig. 3226 represents a mortising machine in which the mortising tool consists of a hollow square chisel containing an auger, and having at its sides openings through which the cuttings escape.

The chisel is rectangular in cross section, but its cutting edges are highest at the corners, as may be clearly seen in the figure.

The work is firmly clamped to the work table and simultaneously to the fence, the upper hand wheel being operated to bring the work-holding clamp down to the work, and the lower one to clamp it so as to press it to both the table and the fence at the same time.

The chisel bar is mounted horizontally in a slide way on a substantial bed that is mounted on a vertical slideway, which enables the chisel bar to be set for height from the work table. It has a horizontal traverse motion or feed, the amount of this motion being governed by the horizontal rod with its nuts and check nuts as shown.

The auger runs continuously, and works slightly in advance of the cutting edge of the chisel, which is passive except when making the mortise.

The chisel bar and auger have a slow, reciprocating motion, and will complete a hole the size of the chisel used. An inch chisel will cut an inch-square hole, consequently a mortise 1" × 4" would only require four strokes forward to complete it. It has a capacity to work mortises from 3/4" to 3" square, and 5" in depth, and any length desired. The boring spindle is driven by an idler pulley, direct from the countershaft.

The bed upon which the timber is placed to be mortised is gibbed to a sliding frame, which allows it to be set to any position, with the chisel straight or at an angle. It is adjustable to and from the chisel bar, to suit the size of material, the under side of which always remains at one height. Adjustments are provided for moving the carriage forward, for regulating the depth of the mortise, the position of the chisel from the face of the material, and the adjustment of the chisel bar, controlling the mortises to be made in the timber.

Two treadles are used upon the side of the machine; the pressure upon one carrying the chisel bar attachment forward, completing the mortise, while the other will instantly force it back when it is desired to withdraw it from the wood, without allowing it to cut its full depth. Provision is made by stops for regulating the length of the stroke as well as the depth of the mortise.

TENONING MACHINES.

In tenoning machines, the lengths of the pieces usually operated upon render it necessary that the work should lie horizontally upon the table, while the shortness of the tenon makes an automatic feed unnecessary.

The revolving heads carrying the cutters in tenoning machines are so constructed that the cutting edges of the cutters are askew to the sides of the heads, but so set as to produce work parallel to the axis of the cutter shaft.

This causes the cutting action to begin at one end of the cutter edge, and pass along it to the other, which enables a steady hand feed, and reduces the amount of power required to feed the work.

Fig. 3227 represents a cutter head for a tenoning machine, _a_, _a_ and _b_, _b_ being the cutters and _c_, _c_, _d_, _d_ spurs which stand a little farther out than the cutter edges, so as to sever the fibre of the wood in advance of the cutter edges coming into action, and thus preserve a sharp shoulder to the tenon, and prevent the splitting out at the shoulder that would otherwise occur.

To bring the outer edge of the shoulder in very close contact with the mortised timber, the cutters are for some work followed by what is termed a cope head, which is a head carrying two cutters bent forward as in Fig. 3228, to make them cut very keenly, as is necessary in cutting the end grain of wood.

The cope head undercuts the shoulder, as shown at _a_, _a_, in Fig. 3229, which is a sectional view of a mortise and tenon.

Fig. 3230 represents a tenoning machine for heavy work, constructed by J. A. Fay & Co., adjusted for cutting a double tenon, the upper and lower heads revolving in a vertical plane, and the middle head in a horizontal plane.

A is a vertical slideway for the heads C, D, carrying the shafts for the cutter heads _a_, _b_. At B is the hand wheel for adjusting D, and at E that for adjusting C. The pulley _d_ is for driving the cope heads, one of whose cutters is seen at _c_. The work carriage H is provided with rollers which run on the slide on K, and is supported by the arm I, which rises and falls to suit the cross motion of H. The fence G, for the work, is adjustable by means of the thumb nuts.

SAND-PAPERING MACHINES.

Sand-papering machines are of comparatively recent introduction in wood working establishments, but are found very efficient in finishing surfaces that were formerly finished by hand labor.

Fig. 3231 represents a sand-papering machine, by P. Pryibil, in which a spindle has three stepped cones on one end, and a parallel roller or cylinder at the other. The steps on the spindle are covered with a rubber sleeve, and the sand paper is cut to a template, and the edges brought together and joined by gluing a strip of tough paper under them. When this has become dry the paper is slightly dampened everywhere except at the joint, and is then slipped on the taper drums. In drying it shrinks and becomes tight and smooth upon the rubber covering with which the drums are provided. These are of different sizes to fit different curves in the work.

Flat work is done upon the table, which is hinged and provided with an adjusting screw to regulate its height, and it can be raised to give access to the drum.

When sand paper is applied in this way, every grain is brought into contact with the work, whereas at first only the larger grains cut when it is used on the faces of revolving discs, as in some machines of this class. Furthermore, when used on drums it is offered ample opportunity to clear itself of dust; it therefore does not become clogged, and, as a consequence, it lasts longer and does more and better work than when used on discs.

Fig. 3232 represents a similar machine, but having a spindle vertical also, so that one face of the work can be laid on the table, which acts as a guide to keep the work square, the table surface being at a right angle to the vertical spindle.

The vertical cylinder or drum is split on one side, and provided with internal cones, so, that by screwing down the nut shown the drum can be expanded to tightly grip the sand paper, which is glued and put on as already described.

Besides these rotary motions, these drums receive a slow vertical motion, the amount of which is variable at the operator's pleasure. This provides for using the full face of the drum on narrow work, while it prevents the formation of ridges or grooves in the work.

For sand-papering true flat surfaces the flat table is provided, there being beneath it a parallel revolving drum, whose perimeter just protrudes through the upper surface of the table. The surface of the table thus serves as a guide to steady the work while the sand-papering is proceeding.

By using sand paper in this manner, every grain of the sand is brought into contact with the work; furthermore, a small area of sand paper is brought into contact with the work, and the wood fibre can fly off and not lodge in the sand paper; while at the same time the angles of the grains of sand or glass are presented more acutely to the work, and therefore cut more freely and easily. Hence the sand paper lasts much longer, because a given pressure is less liable to detach the sand from the paper.

The machine is constructed entirely of iron, and the drum is intended to revolve at about 800 revolutions per minute.

Fig. 3233 represents a sand-papering machine in which a long parallel cylinder is employed, the work resting on the surface of the table and being fed by hand. In using a machine of this class the work should be distributed as evenly as possible along all parts of cylinder, or one end of the cylinder may become worn out while the other is yet sharp; this would incapacitate the machine for wide work unless a new covering of sand paper were applied.

Fig. 3234 represents a sand-papering machine constructed by J. A. Fay & Co., for finishing doors and similar work. The frame constitutes a universal joint enabling the sand paper disc to be moved anywhere about the door by hand. An exhaust fan on the top of the main column removes the dust from the work surface. The head carrying the disc is moved vertically in a slideway to suit different thicknesses of work.

Fig. 3235 represents a self-feeding sand-papering machine constructed by J. A. Fay & Co. It is made in three sizes, to work material either 24", 30", or 36" wide by 4" thick and under; it has a powerful and continuous feed, and gives to the lumber a perfect surface by once passing it through the machine.

The feeding mechanism consists of six rollers, in three pairs, driven by a strong train of gearing. The upper feeding rollers, with the pressure rollers over the drum are lifted together in a perfect plane by the movement of four raising screws, operated by a chain and hand wheel. The lower feeding rollers always remain in perfect line with the drums.

It is supplied with two polishing cylinders, placed in the body of the machine, on which the upper frame rests, both having a vibratory lateral motion for removing lines made by irregularities in the sand paper. The finishing cylinder is placed so that the discharging rollers carry the lumber from it, thus running through and finishing one board, if desired, without another following, and these rollers are arranged for a vertical adjustment to suit the dressed reduction on the material to be worked. The roughing cylinder carries a coarse grade of sand paper, and the finishing one a finer grade. They may be driven in opposite or in the same direction, as may be necessary. The lower frame is hinged at each end to the upper frame, so that by removing a pin, either cylinder can be reached by raising the frame with the screw and worm gear, operated by a hand wheel at the end of the machine.

A brush attachment (not shown in the cut) is now placed at the end of the machine just beyond the finishing cylinder, which is a most complete device for brushing the material clean after it leaves the sand-papering cylinders.

Fig. 3236 represents a double wheel sanding machine by J. A. Fay & Co.

This machine is intended for accurately finishing the tread of the wheel ready for the tire, and is one of the most useful and labor-saving machines that can be placed in a wheel shop.

The frame is built entirely of iron, and has a heavy steel arbor running in long bearings, with tight and loose pulleys in the centre. On each end of the arbor is a large sand paper disc for polishing the tread of the rim.

The wheel to be finished is laid on a rotating carrying frame, having two upright drivers. These are attached to a jointed swinging frame, with flexible connections, adjustable to suit wheels of varying diameters.

The first section of the jointed frame is driven by a shaft and bevel gears, and swings upon it. The second one has the wheel-carrying frame, and swings upon the extreme end of the first one, and is driven from it by a chain connection.

Fig. 3235.

Fig. 3236.]

A roller wheel is secured at the bottom of the leg, affording a floor support; also a chain to regulate the proper distance of the wheel from the discs.

A wrought iron supporting frame is attached upon each side of the sand paper discs, adjustable for different sizes.

The wheel when placed in the machine is carried by the gearing against the sand paper discs, which finishes the tread in the most accurate and perfect manner.

Machines are made both single and double. The latter are the most desirable, as the operator has only to place a wheel in position on one side, when it feeds and takes care of itself.

By the time this is done, the wheel on the opposite side will be finished and ready to be removed, when a fresh one is put in, and the operation continued, the only care required being to put in and remove them. Its capacity is 150 set of wheels per day, and it will do the work better than can be done by hand.