How Parts are Assembled in the Factory A KORERO Report

Korero (AEWS), Volume 2, Issue 13, 3 July 1944, Page 16

How Parts are Assembled in the Factory A KORERO Report

In Korero No. 11 we published some pictures of a prefabricated bouse being erected at Lower Hutt. This story tells you about the work that is done on the parts of those houses before they reach the site on which they are to be erected.

Everyone has seen pictures of assembly lines, with rows of cars or trucks moving slowly along, growing as they move, until the finished product rolls off the end, ready to drive away. Have you ever seen a line of houses coming down an assembly line ? Perhaps not, but here in New Zealand you can see something which comes very close to it.

When you look at an assembly line, what you don’t see is the organization that makes it possible, the network of smaller workshops making all the component parts that come in to be assembled. One shop turns out carburettors, another wheels, others pistons, radiators, nuts, and bolts, and so on, and the products of each flow into the assembly line as rivulets flow into a stream. This.prin-

ciple of making parts first is called “ prefabrication ” : it depends on the fact that it is quicker and more efficient to have a thousand identical parts made by one shop than to have them made in ten lots of a hundred each by ten different shops as they are required. If a man knows that he will be called upon to produce thousands of identical parts, he will think out ways and means of doing the job more efficiently, of saving labour, and so on. Probably he will think out, or procure, machinery to speed up and simplify the routine work. Here is the story of how this principle is applied to houses. Let us follow the timber as it goes through the factory. Rough-sawn timber is put through a machine known as a “ four-sider.” This is an affair of whirling knives, on the same principle as the buzzer, which turns out four-by-twos, dressed smooth and squared on all sides, and does it at the rate of up to 25,000 feet per day. The timber then comes, in random lengths, to the first saw. The complete house requires a certain definite number of boards of certain definite lengths. The exact lengths have been worked out, and numbered patterns of each hang on the wall before this saw. The operator casts a skilled eye over each “ stick ” as it comes to him, decides what lengths he can get out of it, and cuts it accordingly, so that the waste is negligible. The lengths range from 2 in. to 8 ft., and each goes eventually into a bin marked with the same code number as that on the pattern. Some, however,

have to be slotted, or have recesses,' called “ checks,” cut in them—these gothrough another process first. Have you ever stood in several inches of mud, cutting out checks with a hammer and chisel, while the southerly wind cuts you to the bone, and your hands grow too numb to grip the tools properly ? As a next step you generally hit yourself on the knuckleshard. Cutting checks is a slow and laborious job, and when done on the site can be, very unpleasant, but the man with the utility saw does it in seconds. This saw takes out a bite an inch wide, to any depth required, and at any angle : six bites, and there is the recess for a six-by-one brace. This operator, also, has a set of specimen pieces hanging on the wall, and can tell at a glance what is required. From this step timbers go on to the bins. The first and longest job in painting a finished house is applying the priming coat and letting it dry. All outside timbers, weather-boarding, or “ rusticating,” come direct from the first saw to the painters, who prime them with the usual red lead and oil mixture. When dry they also go into the bins, so that the house is built ready primed. The bins stand in a long row across the factory. Into them flow all the cut and treated timbers from the first section of the work, and from them, usually from the other side, are drawn such timbers as are necessary for the panel being made. You can’t put a complete house on the back of a truck and deliver it, so

the house must be broken into pieces of an easily handled size and shape. These pieces are called “ panels.” There are seventysix different panels available, each with its code number, and each composed of so many numbered boards or timbers from the bins. A house takes from seventeen to thirty-nine exterior panels, and from thirty-four to forty-seven interior panels, according to the type of hou'se being built. There are also the porch panels, eight in number, and the rooftrusses, of which seventeen are required for a simple gabled roof. This does not mean that all the houses thus produced will look alike : actually forty-six different types of houses, of varying sizes, can be built from a combination of different numbers of panels.

The actual assembly of panels is done on jig tables. These are low benches, with steel flanges and channels into which to drop the timbers. There are six of these tables, but by the ingenious use of interchangeable flanges the whole seventysix panels can be made up on them Timbers are drawn from the bins, dropped into the appropriate channels, the braces drop into the previously cut checks and the whole is nailed up. Tarred paper is laid over the frame, and the weatherboard or rusticating is drawn from the bins, laid on and nailed. The panel is then lifted off, given a number and stacked. The simplest wall panel contains only nine pieces—the largest has thirty-two. They are stacked in a definite order, so many panels to a stack. This is the

order in which they will be loaded on to the truck, so that they may be unloaded in the order in which they will be assembled on the site of the house. It may remind you of a meccano set, but the whole process is an example of expert organization. It is this sense of organization and control that is the most impressive feature of the whole factory. Some of the most important parts of a house come under the joinery department—doors, window sashes and so on. In this factory the join-

ery is made in a parallel department. The timber used for sashes is mostly redwood. New Zealand totara is good but takes so long to dry that stocks of it are unobtainable at the moment. The timber comes in in the usual .~ay, is dressed, squared and planed to accurate sizes, by buzzers, the planer and the ” thicknesser.” Then it passes to the moulder, or shaper, which cuts it to the shape required, putting in the recess for the glass and so on. Another saw cuts it into required lengths, further machines cut the mortises and tenons, and the pieces are sorted into lots.

There are quite a number of clamps hanging on the wall. If you look closely you will find that the dust is setting thickly on them, for the clamping of frames is done by another machine which operates at the touch of a foot. Wedges are glued and driven in, aluminium “ star pins ” driven through to strengthen the whole, and it is unclamped and put aside for the glue to dry. Aluminium nails, by the way, are used so that, if it is required to plane a shade off the sash the nails will not gap the plane.

Next we come to the magician with the glass-cutter. A lightning scratch, a gentle tap, and a six-foot sheet of glass falls into two halves. He places a “ three-light ” sash on his bench, runs putty round the edges, cuts three panes of glass, drops them in, tacks them in place with a selffeeding hammer, trims off excess putty, and the window is off the bench complete, exactly two minutes after it started as a bare sash. If you think that’s as easy as it sounds, try it.

The joinery is now fitted into the panels, but the pins are knocked out of the hinges and the sashes are removed during transport and erection. Alongside the factory is a long, low building, rather dark and damp inside — just the right atmosphere for drying and maturing concrete. Here are made all the concrete parts for the houses—wash tubs, coppers and hearths, fireplace surrounds and hearths, even the fence posts, clothes posts, and the back steps are precast. The chimneys are made here too, in sections to be built up on the site, like a child’s blocks.

All this concrete has to mature for some weeks before it can be used, so that much of the workshop is filled with assorted shapes of concrete products. Did you ever stand in a factory, fascinated by what seemed miles of whirling countershaft and clacking belts and moving very warily because there always seemed to be something whizzing viciously just behind your ear ? There’s nothing like that in the prefabricated housing factory. The building is big,

airy, well lighted, and clean and. the machines are well spaced apart. There are no belts visible : each machine is driven by its own electric motor, and where belt drives are necessary they are under the machines. The floor is not littered with piles of sawdust and shavings : each machine has over it a hood connected by suction pipes to the blower, or exhauster fan, which draws all waste into a common bin. Two truckloads of sawdust and shavings leave the factory daily, so if you can think up a profitable use for sawdust here is the foundation, of a fortune.

Almost all tradesmen are prejudiced against prefabrication at first, but once they understand its workings they become enthusiastic supporters of the system. The men who work these machines are doing a necessary job, but over and above that they are craftsmen, doing a job well, and they are justly proud of it. One of the early objections to prefabrication, particularly on the part of tradesmen, was that it was going to throw skilled men out of work. The answer to that is that there is such a demand for houses now that there will be work enough for all for some years to come, even

with mass-production methods cutting routine labour to a minimum.

After —one operator suggested that if the scheme were to progress as*, it shows every sign of doing, there was no reason why the worker should not have more leisure-time to devote to his own interests. That, however, is in the future. It’s a new idea, so new that many people distrust it instinctively, but it is in line with modern industrial trends, and prefabrication of houses is here to stay.