Inspection and assembling
Ford shop inspection is, of course, thorough, and begins before the unloading of incoming rail shipments, by analysis of samples of bar steel and forgings, and pig-iron.
The inspection of material and components in process of finishing in the various shop departments, is in charge of one chief inspector, who began as machinist with the first Ford car model built in the shop at 81 Park Place, 1901-2. It is worthy of note that when Henry Ford began at 81 Park Place, 1901, he worked as a machinist on the first Ford car with his own hands and had with him one young machinist, one draughtsman, and one boy. The draughtsman is now Ford factory superintendent, the young machinist is now chief inspector, and the former boy is now the metallurgist-in-chief of the Ford Highland Park plant, which may be taken as evidence that Henry Ford was unusually fortunate in the selection of his first three men, or, again, as evidence that he is willing to aid in advancing individuals who once begin to work for him.
The head inspector has three assistants, two for day work and one for night work, and about six hundred others under him, variously employed but all classed under the general title of "inspectors." All inspectors take orders from the head inspector only, but of course respect the convenience of the foreman of the department in which they are stationed.
The inspectors are divided into classes having special duties and designations. The "incoming-material inspectors," one hundred and twenty in number, deal with all material received partly finished from outside suppliers, inspecting to Ford Company's specifications and drawings.
The fifty foundry inspectors inspect every piece of casting made by the foundry, first in the rough, then as to tumbling, snagging, and visible defects, and see that all work sent from the foundry to the machine shop is to all appearance satisfactory.
The incoming-material inspectors and the foundry inspectors pass upon materials entering the factory departments where they are to be finished and completed.
The factory departmental inspectors are divided into three classes, as follows:
- (1) "Machine inspectors," who are inspectors of machine work in progress.
- (2) "Operation inspectors," who inspect work after the completion of individual operations.
- (3) "Floor" or "final" inspectors, who inspect completed components only. These are day inspectors.
In addition there are about one hundred night inspectors, mostly acting as machine inspectors, some six or eight "rejected-components" inspectors, and finally, about twenty "scrap" inspectors, whose duties will be presently specified.
The machine inspectors, one or more in each machine-shop component -production department, move from one machine to another and note work in progress. There are about one hundred and twenty day machine inspectors and about one hundred night machine inspectors. The machine inspector notes any fault in any operation in progress, and may either correct faulty tool-setting himself, or may call the department -foreman's attention to the fault, or may order a change of tools or may call a tool-setter to remedy a fault. Machine inspectors enough are placed in each department to cover all operations in that de partment at frequent intervals, so that no faulty operation shall proceed for any . great length of time. The office of the machine inspector is highly important and his powers are large and are exercised at discretion. The operation inspectors inspect the work at certain periods in progress of finishing.
The floor or final inspectors deal with components in completed form. Each department is cleared daily of wasters or components rejected by the final inspectors, and all wasters from all machine-shop departments are taken at once to the same room, close to the machine-shop superintendent's office, where each waster is carefully examined by one of the six or eight wasters inspectors to see if the rejected component can be made good.
All wasters finally condemned by these wasters inspectors then go to the "scrap" inspection department, and there undergo individual examination by the twenty scrap inspectors who place the blame of the scrap-making where it belongs. The wasters inspectors may call on the head inspector, and the head inspector may summon the foreman of the production department where the waster was originated, and the machine-shop superintendent may be notified, so that the waster makes plenty of trouble for those whose faults assisted in its production. The same procedure may be followed in the scrap-inspection quarters, so that all in fault are very likely to be made fully aware of vigorous disapproval of scrap production even as a rare performance.
Every effort is made to save everything which can be profitably saved, and to place blame where it belongs, with a view to curing faulty practice of every description.
The Traveling Inspector
It often happens that matters under discussion with an outside supplier can be soonest brought to a mutual agreement by a face-toface talk and in such intance a traveling inspector is sent to the outside supplying factory. In cases of sufficient importance the head inspector may go to an outside factory, though offidal hag plenty to do at home, and leaves the Ford shops in cases of emergency only.
Inspection Form Blanks
Form 706, "Shop Inspection Tag," size 2 1/16 wide by 4 3/8 inches long, is wired to the receptacle containing finished components by a floor, or final inspector, only. No other inspection official is authorized to use Tag 706. It is printed in black on stiff white paper, filled by the final inspector, who makes the inspection and wires the tag to the components receptacle, where it remains until the components are used in an assembling department . The inspector dates the tag, fills in the component symbol inspectors Report NYE-8003 Inspector's Report space, directs the finished components to destination, signs his initials, and certifies accuracy of dimensions and finish. on Defective Material. Printed in black on one side only of substantial white-paper form, 8% wide by 5}£ inches high. Filled by the department inspector with carbon duplicate, sent to the head inspector, who signs his name to both original and carbon , sends the carbon to the purchase agent, and files the original; when final adjustment is made it is recorded by the head inspector on his filed original, completing the entire record.
Triplicate form, green, pink and yellow colors, printed in black, serial letter black and same serial number in red, on one side of thin paper, only, 8 inches long by 5 1/4 inches high. Green original and pink and yellow carbons. This is the report on incoming material, filled by Giving a good idea of the problems and the work involved in its assembly.
incoming-materials inspector, signed by his shop number; the three forms are sent to the head inspector, who appends his signature to all three forms, sends the green original to the purchase department, the pink carbon to the stock department, and files the yellow carbon in his own department.
Ford Shops Assembling
Ordinary machine-shop assembling practice stations the principal component in a convenient place on the shop floor, sometimes over a pit, or on a suitable platform having more or less elevation above the shop floor, on horses or on the bench, as may seem best, and proceeds with the assembling by bringing the other components to the principal component and applying and fixing them to the principal component which remains in the one place until the assembly is completed.
It is also ordinary practice to place all the components of a given assembly, as of a lock, or a dozen locks, in a box, or in a box with twelve compartments, and to pass this box to an assembler, who may wholly assemble each lock, or perhaps may partly assemble each lock and pass the box on to one or more assemblers who complete the assembling; or to place the components of (say) a watch movement in each of a series of boxes and pass these boxes to the first one of a line of assemblers, who does his part of the watch assembling and passes the box on to the next man, and so on, until the watch is completely assembled. All of this well-known practice may divide the assembling operations needful to produce the completed unit assembly more or less minutely, and, up to a certain limit the greater the number of the assemblers in the fine, the less the total assembling time will be and the better the work of assembling will be done.
These methods are used for small unit assemblies only, and the Ford motor and chassis assembling methods are believed to show the very first example of minutely dividing the assembling operations of so large and heavy a unit assembly as an automobile. These Ford motor and chassis assembling lines are believed also to show the very first examples of chain-driving an assembly in progress of assembling, and hence are worthy of the closest study by all builders of comparatively small assemblies of any description.
The Ford shops assembling practice is to place the most suitable component on elevated ways or rails, and to carry it past successive stationary sources of component supply, and past successive groups of workmen who fix the various components to the principal component, 1 until the assembly is completed and ready to leave the assembling line. In some cases, where the shape of the component is unsuited to travel on rails, the principal component is pushed along on a finished iron table from one man or group of men to another man or group of men, past sources of component supply, each workman or group of workmen completing the placing, or the placing and fixing, of one component before moving the assembly in progress to its next station.
In case the assembly in progress moves on elevated rails or ways, it is common Ford practice to drive the assembly in progress by means of a slow-moving chain, and if the components are perfectly to gauge, so that all operations can be performed in predetermined times, it is better to drive the assembly in progress at a fixed suitable speed by chain, at a uniform rate, than to move it on the ways by pushing.
This Ford method of moving the assembly in progress has effected remarkable labor-saving gains over stationary assembling with all components brought to the one point for each assembly, the labor-saving gains being in all cases accompanied by great reductions in floor space required for the assembling operations.
Thus, up to September, 1913, the Ford car chassis assembling occupied 600 feet length of floor space, and required 14 hours of one man's time to assemble one chassis, standing still in one place while being assembled.
April 29, 1914, with the chassis chain-driven while assembling, 1,212 Ford chassis were assembled on three parallel elevated-rail assembling lines, by 2,080 hours of labor, giving one chassis assembled for each 93 minutes of labor, as compared with 840 minutes of labor in September, 1913.
The stationary chassis assembling in 1913 took 600 feet in length of floor space, while on April 29, 1914, the assembling lines were only 300 feet long.
As for Ford motor assembling, in October, 1913, 9,900 labor hours were required to assemble 1,000 motors in one day, which gives 9 hours 54 minutes = 594 minutes for each motor assembled; May 4, 1914, 1,003 motors, chain-driven on rails, were assembled with 3,976 labor hours, or 238,560 minutes = 237 minutes and 52 seconds time for each motor-assembly completed, a saving of 356 minutes 8 seconds = 5 hours and 56 minutes, per motor. In other words, more than 23^ motors were assembled on May 4, 1914, in the time it took to assemble 1 motor in the month of October, 1913, when the motor assembly was made by first-class American mechanics, working in what was believed by the Ford engineers in the month of October, 1913, to be the very best manner possible.
Besides these almost unbelievable reductions in assembling time, the Ford shops are now making equally surprising gains by the installation of component-carrying slides, or ways, on which components in process of finishing slide by gravity from the hand of one operation-performing workman to the hand of the next operator, this use of work slides being in some instances combined with operation divisions.
All of this Ford practice is of great importance to manufacturers at large, because the Ford engineers assert that these improved methods of handling work by slides, of moving assemblies in progress, and of minutely dividing assembling operations, can be applied to any and all small-machine manufacturing, with very large reductions of labor-cost.
The writer of these Ford stories has had sixty years of machine-shop experience, ranging from cleaning castings and helping in the blacksmith shop to holding the position of chief draftsman and superintendent, and he believes that these assertions of the Ford engineers as to the extended scope and applicability of these new methods of work-in-progress handling and assembly moving, are broadly true.
I should say, in addition, that it was only at the end of three weeks of study and photograph-taking in preparation of this chapter that I became aware of the underlying principles by the application of which these incredible labor-savings of the Ford shops have but very recently been obtained.
What is more, if the reader experiences but a very small part of the surprise and admiration the writer experienced upon being made aware of this new Ford practice, he will certainly approve of the space devoted to full illustrations and descriptions of the Ford new practice in the directions specified. The Ford engineers are now moving over 500 machine tools in the Highland Park shops, and are having a large number of new machine tools constructed, many of them showing striking novelties of design, in order to take full advantage of the new things they themselves have learned in the last ten or twelve months.
The new Ford method of finishing the cylinder bores of small gasengines by a rolling process, illustrated on page 126, gives an excellent interior cylinder surface, and is here first illustrated and described. This method of cylinder-bore finishing costs but very little, and is believed to produce results far superior to those obtained by the very best cylinder grinding practice, at a small fraction of cylinder-bore grinding costs, and this first disclosure of the Ford cylinder-bore rolled finish is highly important gas-engine construction news.
The Ford Piston and Connecting-Rod Assembling
To show what may be done by simply dividing an operation seemingly already reduced to its lowest terms, and placing a short work-slide lengthwise of the assembling bench; the first example of the improved Ford practice here illustrated and described is the piston and connectingrod assembling, changed within the last two months, so that now 14 men assemble 4,000 pistons and connecting-rods in one 8-hour day, instead of the 28 men employed to do exactly the same work less than two months ago, and with no change whatever in the tools used, nor in the ultimate operations performed.
In addition to the labor-time saving, the present practice of piston and rod assembling includes an inspector, who gauges and inspects each piston and rod assembly, with the result of no rejections from the motorassembling line. With the former practice, where one man did the whole job of piston and rod assembling, numerous returns were made from the motor-assembling line, causing costly delays in the motor assembling, to say nothing of the costs of pulling down and reassembling the faulty piston and rod assemblies.
Ford Pistons and Pins
The finished weights of Ford pistons vary, maximum, about six ounces. Each piston is weighed and marked on the head by a heavy center-punch used without a hammer, with one, two, three, or four center marks, dividing the pistons into four weight classes, maximum weight variations in each class three-quarters of an ounce. After inspection , the inspector places the assemblies on one or another of four shelves, according to center marks on the piston head, and the pistons are paired for weight on opposed crank-throws by the motor assembler. The pistons and pins come to the piston-and-rod-assembling bench with the pins in the pistons. The rods come to the bench by themselves.
The work bench is covered with sheet metal on top. In the old style, where each man did the entire job (average time about 3 minutes), each bench had 7 piston-holding special vises on each side, with no inspector, and no inclined work-slide over the bench—14 men to each bench, 2 benches, 28 men in all, who assembled 175 pistons and rods, average, in 9 hours of each man's time, or about 3 minutes 5 seconds time, each. Operations, tools, and benches were the same as now used in working the new methods, save that 7 of the 14 vises are now removed from each bench. No inspection, and many returns of faulty piston-and-rodassembling from the motor-assembling line attended the older practice.
The flat-top sheet-metal covered benches are 14 feet long and 4 feet wide. Here was a 3-minute operation, very simple: push pin out of piston, oil pin, slip rod in place, slip pin through rod and piston and tighten the pin-pinching screw in the rod top-end, and place and open the pinchingscrew split pins; and, although the time was not very small and the work not faultless, no one had studied the job carefully, or held a stop-watch on the operations to find how the 3 minutes were actually expended. Finally the motor-assembling foreman analyzed the time with the stopwatch and found that 4 hours out of the 9-hour day were spent in walking—that is to say, in body movements of each assembler made by moving his feet.
In a day or two the foreman had split the single man into 3 men, and reported to the machine-shop superintendent that he had no use for 14 of the 28 men on the piston-and-rod-assembling job, and the superintendent laughed at him. Seeing convinced the superintendent that the laugh was misplaced, and he then said that it was surprising that the job had not been changed before. It is of no use whatever to tell this story without detailing it as minutely as a split second-hand details operation-motion time-losses; therefore, one diagram and three photographs are shown, together with a fairly complete operation-time analysis so that the reader can see for himself much more than he could learn as a mere uninstructed spectator in the Ford shops, watching this piston-and-rod-assembling job in actual work.
Old-Style, One Man Performing Six Operations
- Operation 1. Drive out pin, with special hand-hammer.
- Operation 2. Oil pin, by dipping end in box of oil. Hand.
- Operation 3. Slip pin in rod-eye. Hand.
- Operation 4. Turn pin to take screw. Screw-driver.
- Operation 5. Turn in pinch-screw. Hand brace.
- Operation 6. Tighten screw, with open-end wrench, and put in cotter-pin; spread pin-end with special tool.
Time 3 minutes and 5 seconds; no inspection; 14 men on one bench. Average production per man, 175 pistons and rods assembled in 9 hours working time.
New-Style, Operation Split Into Three Divisions
- Bench provided with slide, 3 men on each side of bench and inspector
- Operation 1. Drive out pin, oil pin, enter pin-end in piston, average time, 10 seconds.
- Operation 2. Place rod in piston, pass pin through rod and piston, with screw-driver turn pin to position to take screw, turn screw in with brace. Time 10 seconds.
- Operation 3. Tighten screw with open wrench, place cotter-pin, by hand, spread cotter-pin ends with special tool. Time 10 seconds.
- Operation 4. Inspection. Inspector gauges piston with flat steel gauge, places piston in pin-holding jig, tries rod to see if rod is pinched tight on pin, then holds piston horizontal in both hands and vibrates it slowly in vertical plane to see that the weight of rod free-end will barely rock pin in piston-pin bushes, and that pin has friction enough in bushes to keep rod from moving freely, a delicate test for pin-fit in pistonbushes .
at one end of bench.
If rod works either too stiffly or too freely the assembly is rejected , goes back to assemblers, and has a larger or smaller diameter pin put in, as case may demand. Actual inspecting time about 8 seconds, leaving inspector 2 seconds time to place the assembly on its proper shelf, according to the weight as shown by the center-punch mark or the marks on the piston head. The best time record for 7 men, 6 assemblers and 1 inspector, is 2,600 piston and rod assemblies turned out in 8 hours, equal to one assembly in 77 1/13 seconds of one man's time. Average time, 2,400 assemblies in 8 hours, with 7 men, gives one assembly in 84 seconds of one man's time, or better than double the work of one man doing the entire job with no inspector , and with a saving of 101 seconds of time of assembling. With inspection, under new style, as said before, there are no returns of pistons from the motorassembling line.
This piston-assembling job teaches two lessons of first importance . The first is that there are great savings in labor to be made by splitting operations to such an extent that the workman does not need to change the position of his feet, and the second lesson is that a work-slide so located that the workman can drop his completed operation out of his hand in a certain place, without any search for a place of deposit, and also can reach to a certain place and there find his next job under his hand, is also a very important time-saver.
The vises are 60 inches apart, so that there is only 30 inches reach required for the pistons and pins, which are placed on the bench after operation 1, ready to hand to the man who performs operation 2, who in turn places the pistons where they are readily reached for operation 3. The slide is used for the completed assembly only, and delivers the com pleted assemblies close in front of the inspector so that not a movement need be wasted anywhere.
In commenting on the late change from the old routine of piston and rod assembling to the new method by which 14 men are made to do more and better work than 28 men did before, the foreman of assemblers said, "We were asleep over that job, asleep and dreaming. I don't see how we came to overlook the possibilities the way we did."
It was in this same assembling department that the first moving assembly line, that for assembling the Ford fly-wheel magneto, was installed. Of course, every one had everything to learn, and this first Ford assembling rail-line was built 8 inches lower than it should have been. The correct height for the magneto assembling, three illustrations given herewith, is 35 inches above the floor for this job. There were the same uncertainties as to the best height in the case of the chassisassembling ways.
In all instances it is of first importance that the workman should stand upright. A stooping posture very soon tires the workman, and greatly reduces his efficiency. When the chassis ran on its own wheels on the floor it brought things about "work-high"; some of the operations were too high for convenience, and platforms were placed on the floor where needful. When the first high line was placed for chassis assembling, with the chassis sliding on its axles on top of the rails, it was made 26 3/4 inches high; two other chassis lines were installed each 24 1/2 inches high, one on each side of the middle 26 3/4-inch rail-line. These two heights, 26 3/4 and 24 1/2 inches, are retained with much satisfaction , the tall men being worked on the high line and the shorter men placed on the two low lines. The Ford engineers attach so much importance to this "work-high" condition that they are now placing a great number of gray-iron raising bases under various machine tools, particularly under presses, to bring the work at such a height that the workman can either stand or sit erect, any stoop being now well known to cause a marked reduction in the worker's output.
The first fly-wheel magneto moving assembling line was installed, ready for work, about May 1, 1913, but the desirability of general application of the moving assembly line to the Ford motor assembling and the chassis assembling was not at once fully conceded by all the Ford engineers.
Fly-Wheel Magneto Moving Assembly
This moving-assembly line is of historical importance as being the first moving assembly placed in work anywhere, so far as revealed by information to date. It is, of course, possible, or perhaps probable is the better word, that the moving-assembly fine has been used somewhere in the world, but it is new to the Ford engineers and entirely novel to me.
If the moving-assembly line has been used elsewhere, probably this publication will bring the previous use to public knowledge. The fly-wheel-magneto-assembling story will not be told in full at this time. The Ford motor is the only one used for automobile driving which fires the charge by current generated by a magneto built directly on the fly-wheel, and hence sure to run as long as the fly-wheel revolves —which, of course, gives a more direct and certain magneto drive than can be had with a separate magneto, gear-driven from the motor crankshaft , after the usual practice. Besides this, the Ford fly-wheel magneto is a novel construction, and it is hoped that it may be fully described at a future date, but at this time such description is outside of the line of thought.
Previous to the installation of this moving magneto-assembling line, the Ford fly-wheel magneto had been a one-man assembly, each workman on this job doing all the assembling of one fly-wheel magneto and turning out from 35 to 40 completed assemblies per 9-hour day. The work was done by experienced men, but was not so uniformly satisfactory as was desired, and was costly as a matter of course, as all one-man assembling must of necessity be forever.
Forty assemblies per 9-hour day, best time for one-man work, gives nearly 20 minutes time to each one.
When the moving-assembly line was placed in work with 29 men, splitting the one-man operations into 29 operations, the 29 men began turning out 132 magneto assemblies per hour, or 1,188 per 9-hour day, one man's time producing one fly-wheel magneto assembly in 13 minutes 10 seconds, a saving of nearly 7 minutes time on each assembly, or more than one-third of the best one-man time.
A new high line with chain-drive was installed for magneto assembling about March 1,1914, when the Ford work day had been shortened to 8 hours. At that time the magneto-assembling force had been improved by substitutions and experience, and 18 men were assembling 11,175 magnetos in 8 hours, or a little more than 7 minutes of one man's time to assembling one magneto. i The chain-drive speed was a matter of trial; it was first made 5 feet per minute, which was much too fast; then 18 inches per minute was tried, and found much too slow; the third trial was 44 inches per minute (3 feet 8 inches), and is yet in use, though the foreman believes it could now be increased to advantage. The chain drive proved to be a very great improvement , hurrying the slow men, holding the fast men back from pushing work on to those in advance, and acting as an all-round adjuster and equalizer.
As soon as the men became accustomed to the automatically moving assembly 4 men were taken out of the line and the production was 160 in excess of previous performance; 14 men working 8 hours assembled 1,335 magnetos, making 5 minutes of one man's time assemble a magneto, as against 20 minutes when one man assembled the entire job. The next attempt at moving the assembly in progress was made with the job of placing the crank-shafts in the en-bloc cylinders. An accident occurred which resulted in personal injury and-put a stop to new installations of the moving assembly for a time, butiin June, 1913, the foreman of the assembling room took courage and split the transmission-cover assembling into 23 operations, not on rails but on flat-top metal tables, the shape of the transmission cover making rail-sliding impracticable. One man assembling the entire transmission cover produced from 20 to 30 assemblies per 9-hour day, 18 minutes for each one.
At the present time 23 men, each working one of the 23 operations for 8 hours, complete 1,200 transmission assemblies, which gives 9 minutes 12 seconds for each assembly, or a little more than one-half the best time with one man doing the whole job. These great labor savings led to the first trial of full-length assem bling ways for motor assembling, in November, 1913. Motor assembling on separate benches gave, in October, 1913, 1,100 men working 9 hours to assemble 1,000 motors.
By installing full-length motor-assembling lines and building some new tools to go into the motor-assembling line, along which the motors in process of assembling are moved by hand, now, May 8, 1914, 472 men working 8 hours assemble 1,000 motors. In November, 1913, it took nearly 594 minutes of one man's time to assemble one motor.
Now, one motor is assembled in 226 minutes of one man's time, as against that 594 minutes in November, 1913. This very great saving is due to the continuous line assembling, to the installation of work-carrying chutes, and to holding the motor as nearly as may be at one level during the entire course of motor assembling.
Some of the savings effected by placing the machines in the line-level are noted in the illustration captions. A complete list of the motor-assembling operations is given on pages 118-127, each followed by the time of performing the operation. A number of the most typical operations are illustrated; and inspection of the machines and methods thus shown, together with the descriptive legends and the data of the number of men employed on each job, will give a much more comprehensive idea of Ford practice in this department than could be obtained from any mere verbal description.
When the two-way cock is opened to admit oil to the overhead measuring cylinder, a float-carrying valve rises until it closes the top air vent. When the cock is opened to deliver oil to the motor-crank box, the float descends, admitting air to the measuring cylinder. Placing this oil-measuring device overhead saved the work of five men. The crank-box oil filling now takes only the time required to move the valve.
A cage of hard-steel rollers running at 450 r. p. m. with fVtncn feed is passed down through the bore and up again. Now worked on drill presses, one bore being rolled at a time: a four-spindle machine now under construction will roll all four cylinder bores at once. The hard-steel rollers are ground in a curve, making then 0.001 inch larger in diameter at the middle, and the cage of rollers is oiled freely while passing through the cylinder bore. This makes an excellent cylinder-bore surface. The Ford model T cylinders, which are 3% inches in diameter, were not finished in any way after reaming up to about April, 1914, when this rolling process (believed to be original with the Ford Company and a new operation in gas-engine finishing) was introduced.
The next chapter of this book on the Ford plant will show the chassis assembling, the body placing on the chassis, and the loading of the Ford cars into railway cars. Succeeding chapters will show the results which the Ford engineers gain by the moving of over 500 machine tools, now in transit. The Ford shops, now having reached a production capacity of 1,200 cars per day, if urged, for the first time are giving the Ford engineers opportunity to draw breath and look about, and do some things that they have never before had time to do. The results of this general overhauling will be fully told in following chapters.