Author: Charles Harold Hayward
Date: Unknown
Publisher: Britannica
Materials
Modern methods of furniture construction are largely based on the availability of man-made materials such as reliable plywood, laminated board, chipboard, and hardboard as distinct from natural solid wood. It is not merely that manufacturers prefer the one to the other but rather that these substances are free from the great drawback fundamental to wood—movement. Natural wood shrinks as it dries or swells as it absorbs moisture from an atmosphere more humid than itself, and this movement must be allowed for in the method of construction. Unless this is done troubles may arise: splits along the grain or open joints on the one hand or jammed drawers or doors on the other. Over the years cabinetmakers have worked out ingenious systems to avoid these troubles in the use of solid wood, but today made-up materials may be regarded as inert if of good quality. To an extent solid wood has still to be used, notably for items that have to be turned, cut to shape, or molded, and for lippings to conceal the edges of manufactured boards; but virtually everything in the form of flat panels is made up.
Natural wood
The increase in the demand for reasonably priced furniture has placed a premium on the economical use of wood. Natural wood is extremely wasteful as a material. Hardly more than 25 percent of the natural substance of a tree actually goes into the furniture made of solid wood. When account is taken of the loss in sawdust in conversion from the tree trunk (taking off the outer slab portions and sapwood) and the further loss in bringing the lumber to usable size in the workshop (the offcuts, waste in sawing shapes, in turning, in planing, cutting joints, and final cleaning up), it becomes evident that much more wood is wasted than used.
Plywood
In making plywood, the veneers are peeled rotary fashion from the log by a long knife fitted to a lathelike machine. The resulting veneer can be of unlimited width to be cut up as required. There is no loss in sawdust, and the peeling is continued until only a polelike centre is left. Much the same applies to laminated board in which both the core material and the outer plies are peeled. In the case of chipboard the timber is merely regarded as raw material to be reduced to fine chips that are dried, compressed, and assembled into boards, with resin glue as an adhesive. Where a natural wood grain is desired, a veneer is flat sliced from a flitch (longitudinal section) selected for the beauty of its grain.
Certain materials, notably chipboard, must be machined, because trimming at the edges by hand almost always shows as a deterioration. It cannot be planed; the plane merely forms dust rather than taking shavings and, owing to the abrasive nature of the material, the edge of the cutter is quickly lost. Consequently, when a panel of a certain size is required, it needs to be machine sawed to size, no further trimming being needed. This is only practicable with a precision saw capable of fine adjustment. Furthermore it requires a saw blade having tungsten teeth to resist abrasion. The same applies to any plywood or laminated board assembled with resin glue.
Another influence on the construction of furniture is the introduction of new types of adhesives in place of the traditional animal glue. Many are highly water resistant, some waterproof. Some can be applied cold, avoiding the complication of heating joints before assembly. They can be cured by heat in a matter of minutes, leaving presses and other apparatus free for other work.
Other materials
Although wood has always been regarded as the traditional material for furniture making, several other materials are now used, either entirely replacing wood or combined with it. Plastic laminate, widely used for table and other tops, is obtainable in various colours and designs and in photographically reproduced natural wood grain. Its advantages are that it resists all liquid stains, is largely heat proof against burn marks, is mark free, and is easily wiped clean. It is laid as a form of veneer on any of the man-made materials—multiply, laminated board, or chipboard, usually with a contact adhesive. As a plastic edging is needed that must be applied before the main top is put down, an essential machine tool is the portable router with veneer-trimming unit. It trims the overlapping edges of the main plastic panel without cutting into the edging.
Metal is also used to some extent, particularly for the stands and legs of furniture. Iron is generally preferred, the parts joined by welding.
Finishes too have been revolutionized. French polish, the traditional finish of the Victorian period, and indeed up to the 1930s, has been largely replaced by gloss or eggshell lacquers, which are sprayed on and are heat and water resistant and are so hard as to be practically mark free.
Storage and transport
Two technologies important to furniture making are storage and transport. The space taken up by furniture in relation to the actual material used in its construction is disproportionately large; when furniture is mass-produced an enormous amount of storage space is required. This applies equally to its transport, especially when it has to be shipped abroad. Consequently a great deal of furniture is made of the “knockdown” type; that is, it can be taken to pieces and stacked flat. A wardrobe made in this way may occupy only a quarter of its assembled space when disassembled. Originally, parts were joined by screw fastenings, but a whole range of fittings has been devised to achieve the same result more easily and with more precision. Most such fittings require little more than recessing or the boring of holes, operations easily machined. Most work on cam, screw, or wedge action.
Woodworking machinery
The decline of the direct link between customer and maker, due to the rapid development of retail trade, was largely made possible by the invention of several woodworking machines, mostly steam powered. Much handwork remained, however, and only large manufacturers could afford major machinery installation. In the early 20th century it was still possible for a cabinetmaker in Britain or Europe to earn a living, though in most cases he installed a basic machine such as a circular saw or worked in a district in which machine shops were available. Thus in Shoreditch, London, whole streets of houses were occupied by cabinetmakers, often several in one house, who made pieces that varied from the finest individual items to the cheapest, turned out in pairs or perhaps six at a time. These men had their machining done in the trade machine shops that abounded in the district. The shops produced nothing themselves but performed any machining that was brought to them: sawing, spindle molding, fretting, turning, planing, and so on. These practices continued up to the beginning of World War I and for a time afterward, although most of the large stores also had their workshops where they made not only individual items for customers but also furniture in quantity to pattern.
But in the U.S., the development of mass-production furniture manufacture was already well advanced, with the principal manufacturing centres at Grand Rapids, Michigan; Jamestown, New York; and High Point, North Carolina. “Grand Rapids” became a byword for inexpensive furniture of reliable quality. Furniture factories have never become large in comparison with the huge production units in such industries as automobiles and steel—few today employ more than 100 persons—because of the continuing need for some hand operations. But their machines for many purposes and the volume in which they operated gave them insuperable advantages in cost over the old-fashioned craftsman. Mass-produced furniture began to have a serious impact in Britain and Europe between the wars.
The shortage of timber during and after World War II made conditions extremely difficult for the furniture maker; but in the 1950s there was a gradual return to more decorative furniture, marked by the introduction of new materials, new machines, adhesives, and finishes.
Modern commercial furniture production may be roughly divided into groups: general furniture—bookcases, wardrobes, tables, etc.; chairs and upholstered suites; and specialized items. Each of these may be further subdivided according to quality and type. In addition to this commercial furniture there are the specialized items made by a few hand craftsmen to special commission. Such goods are necessarily expensive, partly because they are individual pieces made singly to design and also because the best selected materials are used. Furthermore, hand methods are largely used that are costly because they are time-consuming. Even in this field, however, the machine has encroached to an extent. Thus a circular saw is invariably installed because its advantages are so obvious. There is no merit in laboriously ripping boards to size when a machine will do the work as well or better.
Though furniture produced by modern hand craftsmen is beautifully made from the best materials, it often requires considerable discernment to detect the difference between it and the best commercial furniture.
Period furniture
In a class by itself is the manufacture of reproduction period furniture. The best work in this field is of an extremely high standard; and, although it often has to make concession to modern materials in using veneered plywood or laminated board for parts, it usually follows traditional methods of construction, at least where visible machine work would be obvious. On the other hand, all veneers are put down in a press, moldings worked on the spindle molder, and shapes cut on the bandsaw or jigsaw.
It is in this work that wood carving is chiefly used. Because of its high cost, carving has largely disappeared from modern commercial furniture, but to the manufacturer of reproduction furniture it is an obvious necessity. From early times and certainly from the 17th century, wood carving has been a separate trade. A highly skilled calling, it demands artistic sense as well as manual dexterity. It has become divided into classes of which furniture and indoor decoration represent only one branch, with further subdivision within the branch.
In the commercial grade of furniture there is wide variation in quality, from the lowest priced goods to high-grade items in which individual hand workmanship is used for processes where the quality would suffer if the machine were used. Thus drawer dovetails are cut by hand, and sometimes even hand-cut joints are used.
Modern factory layout
Most modern factories are laid out on mass-production lines. The earlier factories often had a cabinet shop, which had its rows of benches for individual work; a cabinetmaker needing machining done carried his wood to the machinist. Today the timber is cut to usable sizes in a main conversion shop and brought to the required moisture content in a kilning section. In the kiln, air is forced through stripped stacks by fans that periodically change the direction of the air flow. In recent years radio-frequency heating has been widely used to dry both natural wood and plywood. The applied radio frequency produces molecular activity in wood and resins (such as those in plywood glue); part of the molecular energy is converted into heat that greatly reduces the time required to dry the wood thoroughly and evenly and to set the glue. The wood is placed in a press between two metal plates to which the power is applied; great thicknesses of wood can be dried evenly by this method.
From the drying section the wood proceeds to the planing and jointing shop, in which it is reduced to the required section and any tenoning, dowelling, or dovetailing carried out. There is also a veneer department, and in many respects this has become one of the most important departments. In it veneers are jointed in width where necessary, and a remarkable recent invention is a machine that sews veneers together with fine fibreglass, the stitching passing through half the thickness of the veneer only. It does this with amazing speed and accuracy. Where required, veneers are matched, giving a balanced appearance; and any small defects are repaired by placing a waste veneer beneath, cutting through both simultaneously, and interchanging the cutout pieces. Veneer pressing follows, and, although multiplate presses are still used to an extent, the tendency in large-production work is toward the progressive presser. At one end of this the resin glue is applied with a spreader, the veneers placed in position on the groundwork, and the whole passed in batches beneath the presser where it is heat cured in about a minute and ejected at the other end ready for further operations.
It is in the assembly shop that the line or conveyor-belt system begins. This is not usually in continuous movement but takes the form of a series of loose rollers over which the work can easily be pushed by one man. Special cramping jigs are set up so that, for example, a wardrobe can be glued up in one operation by power-driven rams. The jig ensures squareness, and the resin glue is cured in a matter of seconds by radio-frequency heating. In fact, by the time the operator has applied glue to the joints of one set of parts, the previous assembly has hardened and can be removed to the conveyor, leaving the jig free for another cramping operation.
From this point onward the work remains on the conveyor belt, passing to a sanding shop where joints are levelled and finally to the finishing shop where it is stained, spray polished, and fine sanded and waxed. Lastly there is a fitters’ shop, where doors are hinged, handles put on, mirrors fitted, and so on.
Before passing to stock or to the packers’ department every piece has to be passed by an examiner who chalks any defect or attaches a small, coloured label indicating that there is a fault in either the woodwork or the finish.
Only a constant flow of orders in large quantities justifies such a setup. Smaller firms contract their veneering to outside specialists, have their turning done outside, and also any other work for which they are not equipped. The aim is to maintain a constant flow of production, which involves a balance in personnel in the various departments to avoid a holdup in any stage.
The production process
A basic preliminary in all furniture production is the provision of working drawings. In a firm of any size there is invariably a special department where full-size drawings are prepared from small-scale drawings provided by the designer. In some cases the designer may make his own full-size, detailed drawings; but in a large firm it is more usual for a draftsman to work out the practical details, though usually in consultation with the designer, who advises on proportions and decorative details. The hand craftsman, in contrast, usually does the whole thing himself. In the small-scale drawing the general form and essential requirements are worked out; the full-size drawing shows proportions and constructional details. A sample piece is made to check the design and cutting problems. Cutting lists are prepared; the cost of materials, fittings, finish, etc. figured; and an estimate of machining and assembly time worked out. When the work is to be produced in quantity, costs are lowered considerably because only one setting of the machine and only one set of cutters are needed for the whole run of any particular part.
Selection of timber, already passed through the seasoning kiln and converted to standard thicknesses, follows. The wood passes to the machine shop, where it is sawed to size, planed, molded, grooved, or rebated as required. When a number of parts must be cut exactly alike, they are clamped in forms having the proper contour and are then brought in contact with high-speed rotating knives that shape the part to proper size as the form rides against a guide on hand or automatic shapers and routers. Intricately carved pieces such as legs are roughly carved on multiple-spindle carving machines. These duplicate a master leg by means of a follower point that is guided along the surface of the model and imparts the same motions to as many as 32 high-speed rotating knives as they whittle the leg blanks. After the rough carving, the pieces are machine sanded and finished by a hand carver.
If veneering is required, this is now done. Jointing follows—tenoning, dowelling, dovetailing, etc. Automatic machines often combine several operations. Exposed parts are sanded on edge belt sanders, three-drum travelling-bed sanders, or belt sanders. Rounded parts are sanded on soft pneumatic drums, and carved parts are sanded on a buffer, a machine in which shredded sandpaper is supported by brushes on a revolving wheel.
Finally the work passes to the assembly shop where door frames are put together, drawers glued up, and carcasses assembled. After the glue has set, the parts may be returned to the machine department for machining that could not be performed before assembly, such as sanding the joints and shaping the edges. Then it returns to the assembly department for final assembly. Air-driven clamps are used when the design permits; otherwise the piece is pressed by hand clamps. Unless electronically cured glues are used, clamps must be applied long enough to ensure a good bond. The completed article is cleaned to remove excess glue, inspected, and hand sanded. Finally, staining and spray polishing is done and fittings added.
In individually crafted work there is always a great deal of fitting to be done—doors trimmed and drawers made to run easily without slackness. In mass-production work this problem would be serious. It is almost entirely avoided by making drawers an easy rather than snug fit and by sanding the edges of doors to templet size so that they automatically fit the carcasses, which in their turn are made to standard size.
The art of chairmaking
Chairmaking has been a separate branch of furniture making since the mid-17th century. One of the most intricate branches of woodwork, it involves odd angles, compound shapes, and awkward joints and at the same time calls for maximum strength, chairs being subjected to more strain than most other furniture. There are three main types of chairs: the Windsor chair, made largely from turned parts, with solid wood seat; the framed type of dining chair with either loose or stuff-over seat; and the upholstered chair.
In Britain the Windsor chair belongs traditionally to the High Wycombe District of Buckinghamshire where beech trees abound. Until relatively recent times men worked in huts in the beech woods making turned parts for chairs. They felled the trees, cut the trunks and larger branches into suitable lengths, and split them into pieces of a section large enough to permit chair legs and uprights to be turned and also to provide lighter members for rails, etc. They turned the parts on a primitive pole lathe in which a cord was attached to a treadle, taken around the wood to be turned and up to a springy sapling anchored at the lower end to pegs outside the hut. The power was supplied by treadle, the cord revolving the wood; then as the foot was raised the spring of the sapling lifted the treadle and at the same time turned the work backward. The turning gouge or chisel could be used on the downward stroke of the foot only, but the economy of effort was amazing. A complete leg could be rounded, the curves and beads formed, and the ends brought to the required diameter in a matter of seconds. Of course, working in green timber enabled the turning to be done much more easily and quickly than if the wood were dry.
These bodgers, as they were called, made only the turned parts and delivered them to chairmaking firms for assembling. They had no overhead expenses, no power costs, and the only lighting they needed in winter was an oil lamp or candles. They were long able to compete with powered workshops.
The manufacture of the Windsor chair of Victorian and Edwardian times was a specialized trade. The seat, invariably of elm, was hollowed out (bottomed) with a form of adze, and the holes for the legs were bored with a brace fitted with a spoon bit held at the required angle solely by judgment. The better chairs had a hooped back of yew. Today this hand work has been replaced by boring machines that are fitted with a jig to maintain the correct angle. The hollowing of the seat is machined to an extent, but the depth is only slight, compared with the early hand work. Furthermore, traditional timbers—elm, beech, and yew—are frequently replaced by imported timbers.
The quality of framed chairs of the dining type varies widely, but perhaps the outstanding general feature of modern dining chairs is the wide use of dowelled joints rather than mortise and tenon. In the late 19th century this had already occurred to a large extent, the chairmaker’s kit of tools invariably including a dowel plate with a series of holes through which the craftsman hammered roughly squared pegs to form the dowels. Today machine-made dowels are universal, with a glue-escape slot cut in. Dowelling is a far quicker and consequently cheaper process than mortising and tenoning, especially in shaped work where the curved part frequently must be joined at odd angles.
When a chair has compound curvature it becomes difficult and expensive to make. A chair back may be shaped in both front and side elevation (and often in plan as well). Taste and experience are indispensable in providing a continuous curve that will be aesthetically satisfying from every angle. Over the years, experience has been built up, especially on traditional models following period lines; a chairmaker’s workshop invariably carries bundles of templets in plywood for the various parts of chairs, with the fullness provided (where necessary) for a good line.
Dining chairs may be made in sets of half-dozens or dozens, or more cheaply in batches of 50 or 100, depending upon the capacity of the factory. In some cases parts are standardized and interchangeable in different designs of chairs.
The upholstering of dining chairs is a separate trade, though carried out in the same factory, and may be of the loose seat, stuff-over, or plywood-covered type. Traditional stuffing materials such as horsehair have largely been replaced by foam rubber and synthetics.
Fully upholstered furniture
The manufacture of fully upholstered pieces is often a separate branch, though large manufacturers often make both upholstered and nonupholstered types. It remains to a great extent a handicraft, for the skill of trained and experienced craftsmen is needed in turning out quality pieces. The standard upholstery foundation consists of a system of coiled steel springs resting on a webbing of burlap and tied to the furniture frame, which may be of wood, fibreglass, or plywood. The springs are embedded in a filling material, such as rubberized hair, foam rubber, palm fibre, or Spanish moss; and the spring system is topped by a thick padding of cotton or foam rubber in sheet form. Muslin is frequently employed as an inner covering for this assembly, while a durable upholstery fabric is used as an outer and finishing cover. Loose cushions are filled with special spring units in a bedding of foam rubber or down; the springs are covered with layers of cotton, and the entire assembly is encased in upholstery fabric.
Only a few mechanical aids have proved satisfactory in upholstering. Multiple layers of fabric can be cut efficiently and economically by machines in production-line operations, and staples are used instead of tacks on less expensive pieces. But the mass production of such components as the basic coiled-spring system and the mechanical handling of such materials as the bedding, or filler, have not proved efficient and economical. Some useful substitutes have been found, however, for the coiled-spring supporting unit; they include the modern nonsagging springs that may be clipped to the frame and the steel bands that are held to the frame by helical springs. Sponge rubber may be molded to constitute a complete seat that is firm and comfortable. Webbed seat frames also are used, and the natural resiliency of wood is utilized in building springy plywood supporting structures.
Comments:
It is insane how much goes into making furniture. Also, it shocked me that ‘Hardly more than 25 percent of the natural substance of a tree actually goes into the furniture made of solid wood.’ Much more wood is wasted than used.
I think disrupting this industry will be very fun and interesting. Furniture is such a large area with so many different hierarchies and distribution channels, it will be a fun challenge to tackle.
