be indicated by two letters instead of one, thus: AA, 9-inch bench lathe; BB, 12-inch hand lathe; CC, 20-inch special lathe; DD, 24-inch forming lathe. Or a 36-inch planer widened to 48-inch, instead of having its patterns and parts marked L, will have those made necessary by the change of width marked L-M, the last letter indicating 48 inches wide. In the same way a 36inch lathe raised up to 45-inch swing may have the extra parts needed marked F-G. The hyphen is introduced to indicate that two machines are being considered in the designation. The letters of the alphabet having been exhausted in this manner, other combinatious may be resorted to, as AB, BC, etc., omitting the hyphen, as only one machine is meant to be referred to. This system will be found to have many advantages, not the least of which will be the ease with which these symbols are committed to memory.

In designing the parts of a machine the list is divided into sub-heads or groups of related parts. An engine lathe list will be divided into the bed, headstock, tailstock, carriage, rests, countershaft, etc., each of these headings including the principal piece mentioned, and all its related parts or appendages. In fixing the designation numbers to the various parts the bed would be 1, and the other parts following in regular order. When all the parts of this group are numbered a sufficient number of blank spaces are left for additions in this group. Then the next group is proceeded with in the same manner. The similar parts in several machines of the same class will receive like numbers, the distinctive letter symbol of the machine designating the individual part, pattern, or drawing thereof. For instance, the headstock of a 20-inch lathe may be designated C40, while that of a 36-inch lathe would be F40, and

so on.

When a pattern or a part is altered the fact is indicated in red ink on the original drawing, and on the pattern a letter X is added to its former designation. Thus, the headstock of a 20-inch lathe when altered becomes C40X, each successive alteration adding another letter X to its designating mark, or in case of several alterations, one X, followed by a figure indicating the alteration, may be used. Thus, for the fourth alteration the mark would be C40X4. The red ink on the drawing gives the date when the change was made. Parts may be numbered in groups with reference to the materials of which they are composed. For instance, numbers 1 to 499 may be assigned to cast iron parts; 500 to 599 to malleable iron parts; 600 to 699 to steel casting parts; 700 to 799 to brass parts, and so on for forgings of wrought iron and steel and for the parts machined directly from the bar stock, etc., since every part made or purchased should have its distinctive number in order to carry out not only the drafting room system but that of the other departments of the works. In all drawings the part number should appear in a small circle to attract attention and to distinguish it from the dimension figures. It

should be placed directly on the part where possible; otherwise at one side with an arrow.

Various schemes have been advocated for storing and filing drawings, tracings, and blueprints. It will be conceded, no doubt, that unmounted blueprints, drawings, and tracings should lie flat in drawers, and be so placed that the title at the lower right-hand corner may be readily accessible. The drawers should be constructed as shown in Fig. 181, with a strip A at the back, 1 inch thick and 3 inches wide, to keep the back edges of the sheets in place and to prevent injury. There should be a separate drawer for the drawings of each machine, whose name and distinctive letter

12"Eng. Lathe

FIG. 181. Drawer for Drawings, Tracings or Blue Prints.

should be plainly marked on its front. A similar drawer for each machine holds the tracings, the two being kept in separate cases of drawers. For conveniently finding and replacing sheets the best method yet suggested seems to be that of separating them into groups of ten by interposing strawboard, properly indexed, as shown in Fig.

182. These sheets perform the double office of ready reference to the sheet wanted, and in the case of tracings they serve to keep them flat. The top sheet of strawboard bears the machine name and letter. This sheet should be an inch larger all around than the drawing or tracing, while the indexed sheets should be still an inch wider on the right-hand side so as to admit of ready indexing with plain figures.

FIG. 182. Index Cards for Drawer. Strawboard.

Blueprints mounted on strawboard may be laid flat in drawers, or be stored on edge, in a case, as shown in Fig. 183. On the shelf beneath each compartment is marked the letter and name of the machine.

Indexing, filing, issuing, and recovering drawings, tracings, and blueprints is undoubtedly best handled by the card system. As each machine is designated by a letter, the first card, pink in color, will bear on its tab the letter of the machine. As the parts of the machine are divided into groups

of related parts, the first card of the group will bear on its tab the name of the group, usually taken from its most important part. For instance, in an engine lathe the groups will be the bed, headstock, tailstock, etc. One of the

from

HEAD

group index cards is shown in Fig. 184, and a machine index card in Fig. 185. The arrangement of these cards and of the others in the different groups is shown in Fig. 186. The group index cards are white. By this arrangement it is very easy to find any particular card wanted. The cards relating to one machine may be divided those of another by a loose wooden partition a quarter of an inch thick if desired. It is considered by some draftsmen as a convenience rather than a necessity.

When blue or brown prints are wanted the chief will give the blue printer an order card of the form shown in Fig. 187. If for blueprints he will use a blue card, and for brown prints a brown card.

12" ENGINE LATHE.

GENERAL DRAWING OF HEADSTOCK.
Drawn.--

_by_.

_by_

by

Alterations, etc._.

Traced,
Checked.

A 2

FIG. 184. Group Index Card, size, 3 x 5 in.
Color, White.

If for brown print negatives he will add the word "negatives" to the title line on the card. This card, properly dated, will be turned in to the chief with the prints when they are completed.

When blueprints are to be mounted they are issued by the chief, and when completed a card will be made for each of them, whether duplicates or not, like that shown in Fig. 188, which is light blue. These cards will be arranged the same as those for drawings and tracings, with tabs for the groups

of parts. The cards separating those of different machines will be red, and of the form shown in Fig. 189.

When blueprints are issued the entry will be made on the cards showing

the date of issue and to what department they went. When they are returned. the date will be stamped in the proper space. When the card is filled up a

new one takes its place. The chief draftsman, receiving a copy of all orders for work sent into the shops, will make his arrangements for blueprints in ample

FIG. 187.-Order for Prints. Cards, 3 x 5 in. Color,

Light Blue for Blue Prints; Brown for Brown Prints.

time to meet requirements. Drawings and tracings are not supposed to be sent into the shops, and the making of temporary sketches of any part in the

effort to hurry the work along should be discouraged, as mistakes and misunderstandings are liable to occur, while by always adhering to the regular system we shall insure the prompt fixing of responsibility for errors, and the smooth running of the routine affairs of the department.

In fact the effort to find "short cuts" in transacting the business of the establishment, while in a certain sense commendable, should only be taken up when it is amply demonstrated that such a course can be safely followed. It is too often the case that a slight saving in one direction may result in a waste of time in another. It will be well to consider the work of the Drafting

Room from rather a conservative standpoint in these respects, as a slight error here is liable to lead to much trouble all the way through the shops. Hence the work here should be done with deliberate care and thoroughness to insure the success, not only of this department, but of those which follow it in the regular routine of manufacturing.