Content from F.W. Taylor, Shop Management
(1) Space for the description of the work and notes in regard to it.
(2) A place for recording the total time of complete operations--that is, the gross time including all necessary delays, for doing a whole job or large portions of it.
(3) Lines for setting down the "detail operations, or units" into which any piece of work may be divided, followed by columns for entering the averages obtained from the observations.
We are now ready for the stop watch, which, to save clerical work, should be provided with a decimal dial similar to that shown in Fig. 4. The method of using this and recording the times depends upon the character of the time observations. In all cases, however, the stop watch times are recorded in the columns headed "Time" at the top of the right-hand half of the note sheet. These columns are the only place on the face of the sheet where stop watch readings are to be entered. If more space is required for these times, they should be entered on the back of the sheet. The rest of the figures (except those on the left-hand side of the note sheet, which may be taken from an ordinary timepiece) are the results of calculation, and may be made in the office by any clerk.
As has been stated, the method of recording the stop watch observations depends upon the work which is being observed. If the operation consists of the same element repeated over and over, the time of each may be set down separately; or, if the element is very small, the total time of,
say, ten may be entered as a fraction, with the time for all ten observations as the numerator, and the number of observations for the denominator.
In the illustration given on the note sheet, Fig. 2, the operation consists of a series of elements. In such a case, the letters designating each elementary unit are entered under the columns "Op.,"
the stop watch is thrown to zero, and started as the man commences to work. As each new division of the operation (that is, as each elementary unit or unit time) is begun, the time is recorded. During
any special delay the watch may be stopped, and started again from the same point, although, as a rule, Mr. Thompson advocates allowing the watch to run continuously, and enters the time of such a stop, designating it for convenience by the letter "Y."
In the case we are considering, two kinds of materials were handled sand and clay. The time of each of the unit times, except the "filling," is the same for both sand and clay; hence, if we have sufficient
observations on either one of the materials, the only element of the other which requires to be timed is the loading. This illustrates one of the merits of the elementary system.
The percentage of the time taken in rest and other necessary delays, which is noted on the sheet as, in this case, about 27 per cent, is obtained by a comparison of the average net "time per barrow" on the
right with the "time per barrow" on the left. The latter is the quotient of the total time shoveling and wheeling divided by the number of loads wheeled.
It must be remembered that the example given is simply for illustration. To obtain accurate average times, for any item of work under specified conditions, it is necessary to take observations upon a number of men, each of whom is at work under conditions which are comparable. The total
number of observations which should be taken of any one elementary unit depends upon its variableness, and also upon its frequency of occurrence in a day's work.
An expert observer can, on many kinds of work, time two or three men at the same time with the same watch, or he can operate two or three watches--one for each man. A note sheet can contain only a comparatively few observations. It is not convenient to make it of larger size than the dimensions given, when a watch-book is to be used, although it is perfectly feasible to make the horizontal rulings 8 lines to the inch instead of 5 lines to the inch as on the sample sheet. There will have
to be, in almost all cases, a large number of note sheets on the same subject. Some system must be arranged for collecting and tabulating these records. On Tables 2A and 2B (pages 160 and 161) is shown the form used for tabulating. The length should be either 17 or 22 inches. The height of the form is 11 inches. With these dimensions a form may be folded and filed with ordinary letter sheets (8 1/2 inches by 11 inches). The ruling which has been found most convenient is for the vertical divisions 3 columns to 1 1/8 inches, while the horizontal lines are ruled 6 to the inch. The columns may, or may not, have printed headings.
The data from the note sheet in Fig. 2 (page 151) is copied on to the table for illustration. The first columns of the table are descriptive. The rest of them are arranged so as to include all of the unit times, with any other data which are to be averaged or used when studying the results. At the extreme right of the sheet the gross times, including rest and necessary delay, are recorded and the percentages of rest are calculated.
Formulae are convenient for combining the elements. For simplicity, in the example of barrow excavation, each of the unit times may be designated by the same letters used on the note sheet (Fig. 2) although in practice each element can best be designated .by the initial letters of the words describing it.
a = time filling a barrow with any material.
b = time preparing to wheel.
c = time wheeling full barrow 100 feet.
d = time dumping and turning.
e = time returning 100 feet with empty barrow.
f = time dropping barrow and starting to shovel.
p = time loosening one cubic yard with the pick.
P = percentage of a day required to rest and necessary delays.
L = load of a barrow in cubic feet.
B = time per cubic yard picking, loading, and wheeling any given kind of earth to any given distance when the wheeler loads his own barrow.
[Transcriber's note -- formula and Tables omitted]
This general formula for barrow work can be simplified by choosing average values for the constants, and substituting numerals for the letters now representing them. Substituting the average values from the note sheet on Fig. 2 (page 151), our formula becomes:
[Transcriber's note -- formula omitted]
In classes of work where the percentage of rest varies with the different elements of an operation it is most convenient to correct all of the elementary times by the proper percentages before combining them. Sometimes after having constructed a general formula, it may be solved by setting down the substitute numerical values in a vertical column for direct addition.
Table 3 (page 164) gives the times for throwing earth to different distances and different heights. It will be seen that for each special material the time for filling shovel remains the same regardless of the distance to which it is thrown. Each kind of material requires a different time for filling the shovel. The time throwing one shovelful, on the other hand, varies with the length of throw, but for any given distance it is the same for all of the earths. If the earth is of such a nature that it sticks to the shovel, this relation does not hold. For the elements of shoveling we have therefore:
s = time filling shovel and straightening up ready to throw.
t = time throwing one shovelful.
w = time walking one foot with loaded shovel.
w1 = time returning one foot with empty shovel.
L = load of a shovel in cubic feet.
P = percentage of a day required for rest and necessary delays.
T = time for shoveling one cubic yard.
Our formula, then, for handling any earth after it is loosened, is:
[Transcriber's note -- omitted]
Where the material is simply thrown without walking, the formula becomes:
If weights are used instead of volumes:
[Transcriber's note -- omitted]
The mistake usually made by beginners is that of failing to note in sufficient detail the various conditions surrounding the job. It is not at first appreciated that the whole work of the time observer is useless if there is any doubt as to even one of these conditions. Such items, for instance, as the name of the man or men on the work, the number of helpers, and exact description of all of the implements used, even those which seem unimportant, such, for instance, as the diameter and length
of bolts and the style of clamps used, the weight of the piece upon which work is being done, etc.
It is also desirable that, as soon as practicable after taking a few complete sets of time observations, the operator should be given the opportunity of working up one or two sets at least by summing up the unit times and allowing the proper per cent of rest, etc., and putting them into practical use, either by comparing his results with the actual time of a job which is known to be done in fast time, or by setting a time which a workman is to live up to.
The actual practical trial of the time student's work is most useful, both in teaching him the necessity of carefully noting the minutest details, and on the other hand convincing him of the practicability of
the whole method, and in encouraging him in future work.
In making time observations, absolutely nothing should be left to the memory of the student. Every item, even those which appear self-evident, should be accurately recorded. The writer, and the assistant who immediately followed him, both made the mistake of not putting the results of much of their time study into use soon enough, so that many times observations which extended over a period of months were thrown away, in most instances because of failure to note some apparently
It may be needless to state that when the results of time observations are first worked up, it will take far more time to pick out and add up the proper unit times, and allow the proper percentages of rest, etc., than it originally did for the workman to do the job. This fact need not disturb the operator, however. It will be evident that the slow time made at the start is due to his lack of experience, and he must take it for granted that later many short-cuts can be found, and that a man with an average memory will be able with practice to carry all of the important time units in his head.
No system of time study can be looked upon as a success unless it enables the time observer, after a reasonable amount of study, to predict with accuracy how long it should take a good man to do almost any job in the particular trade, or branch of a trade, to which the time student has been devoting himself. It is true that hardly any two jobs in a given trade are exactly the same and that if a time student were to follow the old method of studying and recording the whole time required
to do the various jobs which came under his observation, without dividing them into their elements, he would make comparatively small progress in a lifetime, and at best would become a skillful guesser. It is, however, equally true that all of the work done in a given trade can be divided into a comparatively small number of elements or units, and that with proper implements arid methods it is comparatively easy for a skilled observer to determine the time required by a good man to do any
one of these elementary units.
Having carefully recorded the time for each of these elements, it is a simple matter to divide each job into its elementary units, and by adding their times together, to arrive accurately at the total time for
the job. The elements of the art which at first appear most difficult to investigate are the percentages which should be allowed, under different conditions, for rest and for accidental or unavoidable delays. These elements can, however, be studied with about the same accuracy as the others.
Perhaps the greatest difficulty rests upon the fact that no two men work at exactly the same speed. The writer has found it best to take his time observations on first-class men only, when they can be found; and these men should be timed when working at their best. Having obtained the best
time of a first-class man, it is a simple matter to determine the percentage which an average man will fall short of this maximum.
It is a good plan to pay a first-class man an extra price while his work is being timed. When work men once understand that the time study is being made to enable them to earn higher wages, the writer has found them quite ready to help instead of hindering him in his work. The division of a given job into its proper elementary units, before beginning the time study, calls for considerable skill and good judgment. If the job to be observed is one which will be repeated over and over again, or if it is one of a series of similar jobs which form an important part of the standard work of an establishment, or of the trade which is being studied, then it is best to divide the job into elements which are rudimentary. In some cases this subdivision should be carried to a point which seems at first glance almost absurd.
For example, in the case of the study of the art of shoveling earths, referred to in Table 3, page 164, it will be seen that handling a shovelful of dirt is subdivided into, s = "Time filling shovel and
straightening up ready to throw," and t = "Time throwing one shovelful."
The first impression is that this minute subdivision of the work into elements, neither of which takes more than five or six seconds to perform, is little short of preposterous; yet if a rapid and thorough
time study of the art of shoveling is to be made, this subdivision simplifies the work, and makes time study quicker and more thorough.
Machine Tool Time Estimation Methods
Methods employed in solving the time problem for machine tools
Updated 29 June 2019, 28 June 2015
First Posted on 3 August 2013
Time and Motion Study - Evolution - Hugo J, Kijne
in the book Scientific Management: Frederick Winslow Taylor’s Gift to the World?
J.-C. Spender, Hugo Kijne
Scientific Management: Frederick Winslow Taylor’s Gift to the World?
J.-C. Spender, Hugo Kijne
Springer Science & Business Media, 06-Dec-2012 - Business & Economics - 192 pages
Many of those interested in the effect of industry on contemporary life are also interested in Frederick W. Taylor and his work. He was a true character, the stuff of legends, enormously influential and quintessentially American, an award-winning sportsman and mechanical tinkerer as well as a moralizing rationalist and early scientist. But he was also intensely modem, one of the long line of American social reformers exploiting the freedom to present an idiosyncratic version of American democracy, in this case one that began in the industrial workplace. Such as wide net captures an amazing range of critics and questioners as well as supporters. So much is puzzling, ambiguous, unexplained and even secret about Taylor's life that there will be plenty of scope for re-examination, re-interpretation and disagreement for years to come. But there is a surge of fresh interest and new analyses have appeared in recent years (e. g. Wrege, C. & R. Greenwood, 1991 "F. W. Taylor: The father of scientific management", Business One Irwin, Homewood IL; Nelson, D. (Ed. ) 1992 "The mental revolution: Scientific management since Taylor", Ohio State University Press, Columbus OH). We know other books are under way. As is customary, we offer this additional volume respectfully to our academic and managerial colleagues, from whatever point of view they approach scientific management, in the hope that it will provoke fresh thought and discussion. But we have a more aggressive agenda.
Updated on 8 November 2019, 8 August 2019, 29 June 2019, 16 March 2019, 28 June 2015