MAKING ADJUSTMENTS: HOW PRESENT PRACTICE IS DEVELOPED INTO STANDARD
PRACTICE
A Concrete Example of Making Adjustments.
In order to make plain exactly how changes are made and take place from
the condition before analysis, measurement, and synthesis are made to
the standard method of doing the work, we shall take a concrete example
and consider it from every phase. This concrete example will be the
assembly of a braider or machine for manufacturing braid, which is a
standard product of the New England Butt Company. With the co-operation
of Mr. John G. Aldrich, who has since become president of the company,
the problem of assembling a braider was studied, both in the laboratory
and in the shop.
It is not generally recognized that ultimate standards can best be
derived in the research room and laboratory. The standard practice
in the plant will be the result of the laboratory practice. If the
finer measurements are made in the shop during the general working
operations, much time will be lost, as shop conditions cannot be
controlled as laboratory conditions can. It has been said that
laboratory experimentation is not directly available in shop practice,
because laboratory conditions differ from shop conditions. They
certainly do differ, but so do the ultimate shop conditions that must
be introduced with the new standard method. The ultimate conditions in
the shop are far nearer the laboratory conditions than are the shop
conditions prior to installation of the new methods.
Former Method of Assembly.
The method of assembly in use before the motion study and fatigue study
were applied was as follows: The base of the braider was placed on an
ordinary low bench, and the various parts were kept in tote boxes or
on the floor. The worker selected such parts as he wished, and put
the braider together according to any traditional method that he had
learned, together with such changes as his whims dictated.
How the New Practice was Derived.
All of the previous assembly methods had been determined by the usual
practice of putting braider parts _together_. In the present case the
braider was taken apart; that is, handled in the reverse order of
assembly, in order to determine from a new viewpoint the best method
of putting the various parts together. The parts were laid out on a
table in the sequence in which they were disassembled. This allowed the
various members of the braider divisions, groups, and sub-groups to be
studied in relation to one another and also separately.
The Two Factors to Be Considered.
The problem resolved itself into two parts:
1. To make the table of the most convenient height and shape to hold
tools and the base group as it grew, while being assembled.
2. To provide the most convenient, temporary, resting place for the
tools and the various parts, before they were carried to the final
position of assembly.
The two parts were so closely related that any modification in one
demanded a modification in the other.
[Illustration: FIG. 25
Easel for simplifying motions and reducing fatigue from work of
assembly. The obvious sequence in our packet method eliminates the
delay and fatigue of the decision of choice.]
[Illustration: FIG. 26
The rigging on a typical Gilbreth packet, as used for the assembly
of braiders and cord machines at the New England Butt Company. This
picture shows only the supporting devices. The length of the supporting
devices is determined by what is to be held upon them. The right
quantity of each kind, therefore, can be put on without counting.
These devices are standardized and are but few in number. They are
specially designed and arranged for picking up parts with both hands,
simultaneously, in an obvious sequence with shortest motions and least
fatigue.]
Outline of the Changes to Be Made.
It became apparent, as the work progressed, that the determining
elements were (1) to shorten, as far as possible, the distance for
transporting the arms and hands while loaded; (2) to arrange the parts
so that their sequence of use would be obvious; (3) to position each
piece so that it could be grasped, transported, and released in the
shortest time with the least expenditure of effort and with the least
resulting fatigue. This meant that the parts should be arranged on
some sort of a holder, or packet, that would shorten the transporting
distance, and that the base group should be placed upon a table that
would carry it as near this packet as possible.
The Solution of the Problem.
A packet, which was practically a table with its top extending
vertically, was placed near the table supporting the base group, and
removable wire rods of the right length were placed in it to support
the various pieces in the best position for grasping. This also
considered the shortest distance for transporting the arms and hands,
whether empty or loaded. These table packets were then modified,
following closely the principles of the design of the brick packet,
especially the hand-hole feature for firm grasping with one motion and
for quick counting of the number of pieces. The packets now consist of
strips of wood two inches apart, horizontally, and two inches apart,
vertically, with holes for pins, interchangeable wire rods, forked
hooks, and other hangers, including interchangeable platforms, shelves,
and vertical supports, extended and positioned for still shorter reach,
and holding in turn such devices as pins to permit the best position
for handful grasping without disturbing the motions of the hand or
the wrist from the natural position, or, that is, the position most
resembling that of normal rest.
The right position for grasping anything with least fatigue is that
position that will permit grasping without turning, twisting, or
holding the wrist at all from its natural resting position, that is,
with muscles in natural balance. It is but natural that this should
be the best way, for it cuts out the positioning motions of the hand
prior to grasping.
Two reasons that the strips of wood were made two inches apart,
horizontally, and two inches apart, vertically, were:
1. Because we desired to get standard data at the same time comparable
with our other standard data. We might also use it for checking, by
means of motions in another trade, the underlying laws of motions,
which we had already deduced in several other trades.
2. Because we desired to have the motions in very nearly the same
places every time, in order to get the extra efficiency and the lesser
fatigue that come from the habit that is formed in this reaching and
grasping.
Many of these laws have since been re-checked and used in methods of
least waste for the transference of skill from one trade to another.
Habits have been formed that permit a much greater amount of output
with less fatigue.
This latticed packet gives us the same dimensions as our
cross-sectioned background. We use four inches in our American work,
and ten centimetres in our European work for these distances--the
difference between ten centimetres and four inches being almost exactly
one-sixteenth of an inch, or so small a difference as to be practically
negligible in work on motion study.
This cross-sectioned packet has, therefore, not only many mechanical
benefits, such as forming supports, either horizontally or vertically
for hangers, but it is also cheap to build, light in weight, and forms
an excellent, relative scale for measurement and for “recording the
surrounding conditions” of a case of micromotion study.
In fatigue study, as in all other work of investigation, it is
difficult to obtain assistants who can “observe what they can see.” Of
those observers who observe what they can see, few will write down what
they observe. Of those rare ones who can observe and will always write
down, few have the habit of maintaining the standard conditions in a
long series of observations. We therefore cross-section the background,
make our devices, when possible, multiples of four inches, and record
the conditions by means of photography, that gives us the key to
causes of deviation from class results.
The modification of the table consisted of making it of such a design
that it could be turned over on its side to form a low table for tall
or double-deck braiders, that would permit motions of less fatigue.
[Illustration: FIGS. 27 and 28
This picture shows the arrangement of parts for the base group of the
braider. It will be noticed that there are three adjustable shelves,
two vertical and one horizontal, for the support in a more convenient
position of certain parts that have to be picked up, for least fatigue,
by handfuls at a time. The various kinds of shelves, clamps, and tables
for different sizes or kinds of machines can be removed or attached to
the packet with one motion of the hand.
Note that the top plate is in position and that the tools are at the
right side of this top plate before the assembler is sent to the job at
all. These parts are arranged in an obvious sequence, and a photograph
similar to this is given to the boy whose duty it is to arrange these
parts.]
Final Adjustment.
In its final form the method consisted of having the parts of the
braider placed on the packet by an unskilled laborer or boy, putting
large tacks on the floor, which located the table at the most
convenient point possible in relation to the packet, which was made
fast to the wall or of easel type, on casters, as the position where it
must stand demanded. In addition, a small gravity, Johnson-Littlefield
packet was attached to the table. This conveyed certain parts, by their
own weight, to a yet more convenient position.[6]
Changes in Type of Work Demanded.
Through this adjustment the assembler used only his most skilled
motions in doing his work. Meantime, the less skilled worker, or
apprentice, who was loading the packet, was learning the assembly
principle, and receiving an apprenticeship in assembly itself.
Change in Mental Attitude.
The effect of the adjustment was to establish easily and quickly a new
set of efficient habits. The parts being arranged on the packet in an
obvious sequence, and the tools being arranged on the table in the
standard position, the worker necessarily performed the work according
to the standard method, which was the quickest and least fatiguing
method, every time that he did it. The result improved his working
method, and acted as an incentive to him to do the largest quantity of
work of the best quality that could be done with a reasonable amount of
fatigue.
Value of This Example.
This example is even more valuable as a method of attack in the
adjustment problem than it is as a specific illustration of a
successful and rapid installation. The workers enjoyed the changes
and accepted them in the best spirit of co-operation. Before using
the method, eighteen braider base groups had been a large day’s work,
per man. With the new method, sixty-six, per man, per day, were
assembled with no added fatigue. The resulting saving pleased every
one concerned, and has assured the maintenance of the method. Like all
other methods, old or new, it must be submitted to certain definite
tests. These it has passed with credit. The outlining of such tests is
our next problem.
[Illustration: FIG. 29
This picture shows a Littlefield-Johnson carrier packet. In this
carrier packet the carriers by their own weight travel downward to a
standard position at the bottom for grasping without looking at them,
as fast as they are individually removed. This packet was invented
by two men in the New England Butt Company, after they had seen our
method of attack, and had begun to think of their work in the terms of
elementary and least fatiguing motions.]
[Illustration: FIG. 30
This picture shows a Gilbreth packet and a Gilbreth bench, arranged
with the carrier packet shown in Fig. 29 for the assembly of a
13-strand braider.]
Summary.
The problem of adjustment and its solution can best be illustrated by
a concrete example. This is of changes made in assembling the base
group of a braider. This example is valuable not only as an incidence
of successful application, but as an outline of an efficient working
method.
FOOTNOTES:
[6] The Johnson-Littlefield packet is a splendid example of the types
of fatigue saving devices that are suggested by employees after they
have been taught the underlying principles of motion study.