Drafting-Room Practice

MACHINERYS REFERENCE SERIES EACH NUMBER IS ONE UNIT IN A COMPLETE LIBRARY OF MACHINE DESIGN AND SHOP PRACTICE REVISED AND REPUB- LISHED FROM MACHINERY NUMBER 2 DRAF TING-ROOM PRACTICE CONTENTS Drafting-Room System, by RALPH E. FLANDERS - 3 Tracing, Lettering and Mounting, by I. G. BAYLEY 17 Card Index Systems, by A. L. VALENTINE, J. S. WATTS and A. B. HOWK - - - 34 Copyright, 1910, The Industrial Ircss. Publishcls of JIAcIIISERY, 49-55 Lafayette Street, Sea7 Pork ity CHAITEK I DRAFTING-ROOM SYSTEM The drafting-room may be said to bear a double relation to the shop. It is the place where designs are originated, and so in a sense it is the head of the shop, furnishing it with the ideas which the machinist turns into concrete forms In iron and steel. On the other hand, the drafting-room may be the servant of the rest of the establishment, doing its calculating and its routine work of testing, etc., lessening the tax on the memory, and leaving the minds of the workmen and foremen free to the task of getting out the product. In different shops, the use which is made of these two functions varies-one or the other of them may be neglected. It is safe to say, however, that there are scores of shops where the drafting-room is looked upon as an almost unnecessary evil, and every cent which is spent in its salaries and supplies begrudged, when this part of the plant might be the servant of the whole, making the work go more smoothly and easily all along the line, from oBce to shipping-room, if the men in charge understood how to get from it its full value. It is this second function which is, perhaps, least understood. In the following, attention will be calI6d to some of the different ways inwhich the drafting-room may lighten the labors of the workmen, lessen the strain on the foreman, and grease the wheels of industry generally. We will neglect entirely the matter of design, therefore, and consider the routine office work of a typical shop. All the ideas which will follow have been put into practical and satisfactory use, some of them for years in the largest establishments in the country. Systems will vary greatly in such widely varying lines as fire-arms, electrical apparatus and milling machines, but in order to take a case which 111 be most suggestive, suppose it is required to equip with a11 necessary drawings, lists and records, a smalI shop buiIding a Iine of machine tools. Numbering the Parts We should have to start with a layout of the machine in hand, done to accurate scale, made either as a new design or a copy of a machine already being produced. The first question to consider is that of numbering the parts and arranging the detail drawings. A good way to number the parts, drawings, etc., is to give to each variety of tool produced a distinctive letter, such as A for universal, B for plain, and C for vertical milling machines, I for shaper, and so on. Attached to this is a number distinguishing the dze. B2 is No. 2 plain miller, L24 might be 24-inch lathe, and so on. The men in the shop and office aIilre soon fall into the way of calling the macllines hIAmrsEs, March, 1905. 4 - .TO. 2-DRAFTING-R00N PRACTICE by these nicknames. Then esch separate part is given a serial num- ber. Thus L20-49 might mean the head cone gear for a 20-inch lathe. Thts designation would be marked on the pattern and serve as a pattern number as well. The arrangement of the parts inorder for numbering depend8 on whether the parts are to be manufactured and fitted in assembling, or fitted esch to the other in the process of making. We may take it for granted that the shop is trying at least to do business in a profitable way, so the arrangement will be considered from a manufacturing standpoint. The parts should then be grouped in such manner that pieces having similar operations involved will be detailed on the same sheets. First mill come the large castings, like the beds, legs...