Mu 6. Sewers Mu 7. Refuse Disposal Mu 10. Building Laws Mu 15. N. O. L. Mu 16. General Articles Agricultural Engineering Ag 1. Drainage Ag 5. Irrigation Ag 9. N. O. L. Military Engineering, Mil. Naval Architecture, Na. Sanitary Engineering, Sa. CHAPTER XII DRAWING-OFFICE SYSTEMS AND METHODS SEC. I NUMBERING, INDEXING AND FILING DRAWINGS GENERAL OBSERVATIONS There are many different systems in use for numbering, indexing and filing original and "outsiders"" drawings; for the requirements of different engineering offices vary very largely. In certain lines of work, however, methods have become standardized; this being particularly true in the case of structural steel detailing; the various offices of the American Bridge Company having been put on a uniform system, and many independent bridge companies having copied their drawing office methods. The requirements in the offices of consulting, manufacturing, municipal and other engineers, however, usually demand special treatment to meet the conditions presented in the most efficient manner. Some typical requirements are as follows: Mr. "A" may demand, at a few moments' notice, all the drawings pertaining to a particular job; Mr. "B," who knows nothing of the customer's name or the job number, requires all drawings showing 7 ft. X 20 ft. multitubular boilers; Mr. "C" remembers, only, that about 5 years ago a certain drawing was made of a special gantry crane, and he wants it immediately so as to answer a telephonic inquiry; or, Mr. "A's" requirements may be more definite, he wants the drawing of the discharge gate of a vacuum pan built for Mr. “D” 3 years ago. In installing any system, it should be examined in the light of requirements similar to those cited; and it should be able, within reason, to take care of the demands of all the above gentlemen, or of others who may come along in the near or distant future. The memory of the chief draftsman should in no wise be relied upon, although in all cases it will be found that a good knowledge of the system is requisite for quick finding of information; brains, and the use of them, being an indispensable adjunct to any filing system. Various systems are described in the following pages, the intention being that they serve as suggestions toward the installation of one best adapted to particular requirements. THE "CLASS AND SHEET-NUMBER" SYSTEM OF NUMBERING AND FILING ORIGINAL TRACINGS In many drawing offices it is desirable that the original tracings. be filed according to "class;" that is to say, that all drawings of millbeds, or of crystallizers, or of 5-ton trolleys for hand cranes, etc., etc., be filed in separate drawers. Instances occur in the case of machine shops or manufacturing plants that specialize on a few lines of work; as, for example, a plant that makes a specialty of sugar machinery, mills, evaporators, vacuum-pans, etc.; or one confining itself to railroad-cars of all types. For such offices, the advantages of having all similar tracings in one drawer (or in contiguous drawers) is obvious. The manager, or engineer, or draftsman, can see, almost at a glance, all that has previously been done on the part of that machine that is under discussion. The same drawings filed under another system could, of course, all be located and assembled by means of a card-index; but the necessity of immediate consultation of all old designs is, in a plant of this character, a matter of frequent occurrence, so that the "topical" filing of tracings is of paramount importance. The system consists in giving to the drawings a number to designate the "class" of the object shown, as the figure before the decimal point, or as the numerator of a fraction; and a sheet number as the number after the decimal point, or as the denominator of a fraction. For example: "86.46" or "" locate the tracing as belonging to class (or drawer) 86, and as sheet number 46 in that drawer, class 86 comprising, say, "Furnace Fronts." 46 It will be seen that the system requires that a comprehensive classification of all articles that are being (or are likely to be) manufactured be made in advance. Herein lies one difficulty in installing the system, for, if the classification and division of parts of machines be not made with judgment and foresight in the first place, troubles are likely to arise after a few years use owing to the too rapid filling-up of files that have a title of too general significance, and from other causes. It should be noted, however, that it is not strictly a "decimal system," so that the troubles due to improper classification in the latter (due to a limitation to ten divisions), are not met with in the "class and sheet-number" system. In making up the classification the following limitations must be kept in mind: (1) Divide sufficiently so that no classes will be likely to have an excessively large number of sheets after a few years use. (Note.A large number of sheets in a class, after, say, 5 years use will not necessarily be cumbersome; because the older sheets, which will be largely superseded, can be left in the older drawers which need seldom be used). (2) Place details that may be used on a variety of machines in a class by themselves; do not classify under a particular machine. (3) Leave a few numbers vacant in the sequence at places where an extension of a particular line seems probable. (Note.-This is a procedure of doubtful utility and should be adopted with caution). (4) Take the first numbers, say from "1" to "10" or "20" for "Shop Tools," "Plant Buildings," etc., leaving several blank numbers for unforeseen plant needs. (5) Have cabinets and drawers constructed so as to be interchangeable, so that new drawers may be inserted at any place where the tracings of one class outgrow one drawer. (5) It is not necessary that there be, at the first, a separate drawer for each class; large envelopes or folders of stout paper may be used in which to file the tracings of one class, several of these folders being placed in one drawer. A Record or Register of the tracings must be kept so that numbers may be kept consecutive, misplaced tracings identified, etc. For the reason that this record will grow unevenly, a bound-book will not do, FIG. 192.-Sheet of register for class and sheet number system of filing tracings. a loose-leaf book must be used (see p. 422). Numbered tabs should be used to mark the "class." A book having sheets 8 in. x 10 in. or even larger is best; and the sheets may be ruled as shown in Fig. 192. When a drawing is completed, the draughtsman ascertains the class number to which it belongs, and then takes from the record book the next number available and enters the date, etc., in this book. It should be noted that there is no sequence of numbers irrespective of class; e.g., there may be drawings numbered 85.746, 86.746, 91.746, etc.; each class starts with sheet No. 1. When the number of drawings reaches a certain point, considerable time will be lost looking through a drawer for any particular tracing, so that a card index will become necessary. This may be arranged on an alphabetical classification for the whole; or with a “class number" classification corresponding to the tracing-filing system for the first division, and either alphabetical, size, or other system of divisions for the second. Thus, if the latter scheme is adopted, a tab card "80 Boilers, M. T., Extn. Front" would indicate the class, and if the cards were arranged in order of size of boiler, the drawing-number for a 66 in. X 18 ft. would quickly be found. Otherwise a hundred or more boiler tracings might have to be examined to find the one wanted. It should be noted, however, that the Record Book described above could conveniently be consulted, and a card index would only be an advantage when the number of the tracings became very large. On each contract, a record of the drawings used should be kept, or a complete set of prints for the job may be made and filed. The system is one that, for a small shop, requires a minimum of indexing and recording; the record book described is the only record that need be kept, and the drawings are self-filing. Furthermore, it is an easy system to which to change any existing unsatisfactory system; or to adopt in places where no system at all has obtained; for a large number of drawings on hand render the making of a classification an easier matter than when all work is in nubibus. THE "CONSECUTIVE NUMBER" SYSTEM OF NUMBERING TRACINGS In this system every tracing made by the firm bears a number of a consecutive order, irrespective of the job number or the date; so that every drawing issued has its own individual number, and no two drawings made by the firm ever bear the same number. What may be called the "job and sheet number" system starts numbering its drawings No. 1, 2, 3, etc., for every job. The "consecutive number" system is very generally used, and should be carefully considered by all engineers starting or revising a drawing office system. There are certain lines of work, however, to which it is not well adapted, as, for example, structural steel detailing; see p. 462. Among the advantages of the system is the fact that there can never be any doubt as to the drawing referred to by a correspondent. A contractor or agent, who might have occasion to refer, by letter or cable, to a drawing of a certain number, would, under the older system have to be careful to give the job number also; if he had already received drawings on other jobs, the omission of the job number might lead to grave mistakes. The system also lends itself well to the indexing of drawings under any desired headings, as reference to any drawing is not complicated by a job number. The "Drawing Number Register Book" used in connection with the system may be ruled as follows: (See Fig. 193.) The "drawing numbers" should be put in in advance with a consecutive numbering stamp; as, if left to the draftsman, "overlapping" of numbers is apt to occur. The register should be kept in a strongly bound book in preference to a loose-leaf book or to cards. |