POWER TOOLS Save Time and Effort
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Time and Motion Study by Black and Decker, Ltd., Proves the Value of Power-operated Equipment
THE study of time and motion, as applied to the use, of power. operated small tools, is an interesting subject. Thai a power tool will do its job more rapidly and with less physical effort on the part of the user than a hand tool is obvious It is in fact, the raison d'etre for power-operated equipment.
A manufacturer or fleet owner who is equipping his shops with such tools may, however, require to know the exact imourit of time and trouble saved by its use. —How much faster and how much easier is it in operation," he may ask, " when compared with the hand variety?"' Many readera may have noticed. the. advertisements for Black and Decker portable electric tools in the pages of "The Commercial Motor," and those of our associated journals. Here, the difference in time between hand and power operation is given, whilst the difference in movement is " shown photographically. The illustrations are so striking that some people: have imagined them to be faked That is certainly not the case,
as a representative of "The Commercial-Motor " has been able to see. for himself.
At. the company's works at Harmondsworth, our repre.aentative watched time and motion study in progress, The photographic side is not so simple as it might appear, for the operator using the toot to be dealt with has to work in darkness, apart from the small amount of light given by a tiny electric. bulb strapped to his wrist
Underground Work The tests which we witnessed were made in a cellar beneath the works, carmine a nat rial darkroom, and the photographic technique employed differed from common practice in flashlight photography.
In normal circumstances the bulb is synchronized to flash as the camera shutter OperlS, but the exact opposite is required for time and motion pictures The camera shutter is open from the moment that the operation starts, and the tiny light on the operator's wrist traces.a movement graphon the photo graphic plate
As the operation ends, a flash bulb, synchronized with the hand-operated
camera shutter, comes into action exactly as the shutter closes. The resultant picture shows the user of a band or electrically driven tool working, apparently. in a good light, All this may sound fairly simple, but long and patient study has been required to produce a background of the correct shade.
Some of the tests were distinctly interesting. Fm instance, a sheet of hard duralamin, in. thick by 6 ins.
wide, took exactly 49 seconds to cut by hand with a hack-saw. With a Black arid Deekei portable electric saw, using the type of bla::e for non-ferrous metals. the time was reduced to 4.!., seconds Incidentally, the time-saving in this instance, as in several others which we witnessed, was much :treater than that claimed ir Black and Decker advertisements Ths reason for this was, perhaps, thaour demonqrator was Mr
I. W. Hughes, the company's sales research engineer.
Some of the other comparative tests demonstrated were also most convinc
ing. Drilling a hole in a piece of 3-in. by 3-in. timber took 40 seconds with a brace and bit, but only 124 seconds with an electric drill..
A half-section 'if neavy gauge 4-in.diameter steel tubc was cut with a portable, power-driven abrasive disc in 50 seconds. Working with a hack-saw, this work would take a man anything up to 20 minutes.
Corrugated iron sheets are difficult to cut across, and for till.; the operator used a special type of cutter in a portable electric saw; the cutter has square teeth, about 3-12 in wide and turns at 2,500 r.p.m
Studding Steel
Setting light studs in a steel joist was another comparative test demonstrated, first with the electric screwdriver and then by hand.
The reduction in physical fatigue of a worker, an all-important point in any form of quantity production, is shown clearly in some of these time and motion pictures An intricate pattern is drawn on the photographic plate by hand-tool operation, whereas when power fools are used: the line is practically straien or almost non-existent,