Tools and patterns

Many factory executives are chiefly concerned with the commercial end of their business, and yet do not possess the technical training to enable them to judge of the relative value of the methods of production used in their own factory. In this they are at a decided disadvantage. Others, however, do attempt to obtain a technical training while engaged in the management of their plant, and profit largely thereby. A thorough training along mechanical lines may not be necessary, but it is an excellent thing for the executive to familiarize himself at least with the fundamental principles underlying mechanical work.

Tool equipment needed to produce a given piece of work need not be understood in detail, but the executive should know the difference between a boring bar and a milling cutter, for instance, and should understand something of the reasons why one type of tool is more suited to the work in hand than another. He should also know what reasons there are for planing a piece of work instead of milling it; or boring and reaming instead of drilling. He should know what class of work requires fitting of such a character that the surfaces must be scraped in order to produce a proper bearing. He should understand something about the various machining processes, and also something about grinding. When a turning operation is indicated and when a surface needs to be ground to secure accuracy are all essential points regarding which a progressive executive should be posted. In addition to these, the production of interchangeable work should be grasped in its fundamentals. He should further know the possibilities of gauging work to produce it with a minimum of expense and within the required limits of accuracy consistent with the commercial quality of the product. If the executive does not understand something of these details he must depend entirely on his subordinates for information.

In order to assist the progressive man and to enable him to secure concise data on tool equipment in a single volume, this book has been written and arranged. The intention of this treatise has been to take up the points mentioned in such a way that a non-technical man can readily grasp the fundamental principles underlying the matters pertaining to tool equipment. It is the belief of the author that executives will find themselves vastly benefited in their work by a careful study of its contents; for it is evident that the man who knows the essential principles underlying the design and upkeep of his tool equipment will be much more likely to obtain maximum efficiency in his product than another who is not so well posted.

Time Factor in Estimating Costs. The problem of estimating costs of manufacturing work is one which is of interest to every manufacturer. In some cases a small factory is engaged in the building of jigs, fixtures, or other tools for outside concerns, and in many cases the firm which is doing the work is compelled to submit a bid in competition with other factories. It is therefore of the utmost importance to make sure that the bid which is submitted to the customer, is such that it stands a fair chance in the competition with the others. In order to make sure that the prices which are quoted to the customer are reasonable and proper, and at the same time that the estimate submitted is made with a wide enough margin to give a substantial profit to the manufacturer, a careful estimate of the time necessary to produce these various pieces which are to be made, is a very important factor.

Broad Experience Necessary. This is one way in which the estimating of costs can be applied, but there are other applications which are fully as important. Let it be supposed that a manufacturing concern is about to submit a bid for making up a large number of pieces which are components of a military rifle; or that a great number of shrapnel shells are to be made, and that the bids which are to be submitted are in competition with those of numerous other manufacturers who are looking for the same work. It is very evident, then, both that the manufacturer who intends to do this class of work should be well prepared as regards his mechanical equipment of machine tools and shop tools, and also that his engineering force be well fitted to make estimates of production and of the costs of machining. In the first place, either of the propositions mentioned requires the services of men who have had long experience in the shop, and also in the planning of operations for work which is to be done in quantity.

Let us take the case of the factory which is prepared to build jigs and fixtures. It is much more difficult for a concern of this kind to make an estimate on the cost of a jig or fixture, than to estimate the production which can be obtained for certain pieces of work which are being put through the factory in large quantities. In the case of the manufacturing of jigs or fixtures, the work must be re-set a number of times during the process of manufacture, and every precaution must be taken to insure accuracy. All these operations take a certain amount of time, the exact amount depending largely upon the skill of the tool-maker. It is therefore difficult to estimate this class of work as closely as the other kind mentioned.

In the case of the manufacturing of a great many parts of the same kind, it is entirely possible for the manufacturer to provide means of holding and locating the work for the various operations which are to be done upon it in such a way that the parts will come to the desired size almost automatically. It is a matter of judgment. Unless the man who is selected for making estimates of this kind is one of broad experience, unless he has had a number of years of actual shop work, together with considerable experience in the actual engineering processes, and unless he has a logical mind, he is very likely to make a complete failure of estimating the cost of work which is to be done.

Usual Causes of Failure. If a jig or a fixture is to be made up, and there is a drawing from which the estimate can be made, the estimator can proceed to take up the various machining operations which are necessary to complete the piece of work, and can jot down the amount of time which he thinks it would be necessary to consume for the various operations, always remembering to make due allowance for the time lost by the tool-maker in looking up tools and in setting up the work preparatory to the machining. Allowance must also be made for careful measuring, in order to insure proper accuracy in the finished product. It will be readily seen that in order to do this kind of work the estimator must be a man who has actually done the work in the factory, in order that he may know exactly how a man would be obliged to go to work to do the necessary machining. The usual causes of failure in estimating a piece of work such as that mentioned, are that sufficient allowances are not made for the setting up and the getting ready to go to work, as well as for time which the man consumes in actually making the fixture.

Secret of Estimating Costs. Briefly stated, the entire secret of estimating costs of production lies in allowing a man sufficient time to do the work, remembering at the same time that there are little incidental things which tend to increase the time necessary, because of a failure to find a certain tool that is wanted, or owing to difficulties that arise when castings or forgings are not made in exactly the right way. All these points must be taken into consideration by the estimator, and the time allowance must be made on an hourly basis. The amount of profit which is to be made by the manufacturer is dependent, to a great extent, upon the overhead expense in the factory. There are many other items, also, which must be considered in making up an estimate of the cost of production. Among them are the matter of the cost of material. In some cases the jig or fixture is made of cast iron, and the pattern is to be made by the same person who is to build the fixtures. In a case of this kind, it is obvious that the pattern-maker's time must also be charged against the account. Also, the amount of stock and the weight of the cast iron which goes to make up the jig, together with the cost of the iron in the jig, must be taken into consideration.

Skilled and Unskilled Labor. Due time must be allowed for the hardening of any parts of the jigs or fixtures which are to be hardened, and it must also be remembered that after a part is hardened, it is usually necessary to grind it, in order that the distortion caused by the hardening process may be removed and the piece may be properly fitted. Of course there are some parts which may be hardened without affecting the jig or fixture in its vital points in the process for example, such things as the heads of screws or their points, a C-washer, a lever, or some other part of minor importance. No matter how small the piece of work may be, however, it must be considered in the making of the jig or fixture, and if there are a number of pieces of the same kind (such as locating pins or something of similar character), several of these pieces can be made up at the same time by a boy or an apprentice, or by a comparatively inexperienced man.

This being the case, the time for these various pieces need not be charged against the work at as high a rate as that charged for some of the actual tool-making. As a matter of fact, it is customary, in factories which do a considerable amount of this kind of work, to portion out such parts as can be made by an inexperienced man, and thus obtain the benefit derived from a cheaper rate of labor. In cases of this kind, the man who roughs out the part leaves a certain amount of work to be done or completed by the tool-maker, doing only the crudest part of the work himself.

No Hard and Fast Rule. There can be no definite rule which a man can follow in estimating costs for work of this character. As stated before, it is always necessary to make a generous allowance for the setting up time and incidental time needed by the workmen in obtaining tools from the tool room, and in making measurements, laying out the work, and so on. Let it be supposed that a number of jigs or fixtures of very similar character are to be made by a manufacturer for an outside concern. Then the estimator would consider that these various planing or shaping operations which are to be done on the work, can be carried along at the same time; if this plan be followed, a considerable saving in time will be effected.

There are so many conditions which affect the building of tools of this type, that it is a very difficult matter to go into the details of the processes used in different factories. About all that can be said in this regard has already been mentioned. A specific example or two could be given, but they would not serve any valuable purpose, and might only confuse the reader. However, in the estimating of costs for work which is to be put through the factory in large quantities, other factors which are more nearly stable come into play.

A Manufacturing Case. Let us now consider the estimating of cost for a manufacturing proposition involving a number of pieces of a similar kind, which are to be made up entirely on an automatic screw machine. Under such circumstances it is a very simple matter to decide exactly which are the tools that must be used for the work, and since the material from which the work is to be made is of a certain character, and, furthermore, since the feeds and speeds of the machine can be easily determined, it is evident that a very close estimate of the actual time needed to produce the work can be obtained without great difficulty. Let us assume further that the job includes a number of pieces which must be machined on an automatic screw machine, that a series of holes must be drilled in each piece, and that a single milling operation is called for. It will be seen that although this piece of work is some- what more difficult to figure than the other one mentioned, it is nevertheless, a simple manufacturing proposition. In this latter case, however, it is necessary to take into consideration the fact that certain tools and fixtures must be made, if the work is to be done properly and is to come within the required limit. A jig and a milling fixture will both be necessary. The cost of these fixtures must be estimated, and the price must be included in the cost which is submitted to the customer for whom the work is to be done.

Overhead Expense. Hourly Basis. The matter of overhead expense is so broad, and furthermore it is of such a variable character, that it is difficult to give anything more than a general idea of it in this chapter. Briefly, the overhead expense of a factory consists of a burden, or load, over and above the apparent cost of labor. That is to say, if a workman spends one hour in turning out a piece of work and if his rate is 30 cents an hour, this burden must be added to the workman's actual cost of labor, in order that the cost of equipment, cost of power, and various other costs, may be taken care of properly. In addition to these matters, the manufacturer's profit, and the depreciation of his machinery and equipment, must also be considered, together with the percentage on the investment, in order that when the work is completed there may be a large enough profit to prove to the manufacturer that his business is a profitable one.*

It is evident that factories of different kinds and under different management would have a proportion of overhead expense that would differ according to the factory conditions and many other items pertaining to the management. In the past few years I have noted a wide difference between the bids sub- mitted by different manufacturers on the same jigs and fixtures. This difference in prices makes it clear that either there is a tremendous difference in the way in which different manufacturers estimate on the same piece of work, or else the equipment which these various manufacturers use for producing the work is in some cases better adapted than in others to the class of work on which these prices were submitted.


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