A small paper clamp should be attached to the scale a short distance from the center opposite the end where the scale which the draftsman is using is situated. This will prevent the scale from being turned over, hence avoiding any other scale, but the one the draftsman is using at the time, turning up. Also when the draftsman picks up the scale by the paper clamp, the end on which the scale he is using is situated will tilt downward and at once indicate to him which end he should place in position to measure what he wishes. Fig. 4 shows one of these clamps in position for the scale as indicated.

Fig. 4. Triangular Boxwood Scale, with Scale Guard or Clamp in Position

Fig. 4. Triangular Boxwood Scale, with Scale Guard or Clamp in Position.

A good ink eraser, together with a metal sheet called an eraser shield in which are various shaped holes, is an indispensable adjunct of the draftsman. In all cases where it is necessary to erase, the ink eraser and the shield should be used. Never use a knife to erase either upon a paper or upon a tracing cloth, for no matter how sharp the knife is, the sheet will be rubbed and ink will not run smoothly upon the place so worked over. A good soft rubber may be used for erasing pencil marks upon either the paper or the tracing cloth, although benzine, turpentine, or gasoline is much better for erasing pencil marks and cleaning off other dirty spots on the tracing cloth. Care should be taken to investigate the status of the insurance and fire laws on this point, since in many cases it is not allowable to use such inflammable materials in houses of the character of the drafting office.

An expensive set of instruments is not necessary in order to do good drafting. A good pen, a bow pen, a pair of dividers, and a compass with pencil and pen point, are all that are necessary. In many cases it is advisable to have two or more pens, one of which should be quite large, one medium, and one rather small.

Many good drafting inks are sold in the open market, and it is no longer necessary for the draftsman to make his own ink by combining India ink with water. In fact this is a distinct disadvantage, since many of the drafting inks on the market are waterproof and while tracings should not be placed so as to become wet, nevertheless it is quite an advantage to use waterproof ink upon them, so that in case they should be accidentally wetted, it will not injure them so that they can not be used.

A sheet of cambric of dark color the size of the drafting board or better still the size of the entire table and drafting board should be used to cover up the work when no one is working, since dust accumulates very readily upon the drafting board and produces much undesirable dirt and, therefore, a very dirty drawing. It is also advisable upon starting work in the morning to brush off the desk and drawing board and to wipe off the T-square and triangles with a cloth. This will prevent dirty marks appearing on the drawing when they are first placed upon them.

Detail Paper. Detail paper is the paper upon which a drawing is made before it is traced or upon which drawings are made to be used by the detailers in making up the details of the structure. Detail papers should be of buff color in order to prevent the showing of dirt upon them too easily, and also to be restful to the eye, and they should present a surface which will take a pencil or ink mark equally well, and they should not be so thin that they will not stand a great amount of erasing.

Many good papers may be bought in the open market. They may be purchased in sheets of a desired size or they may be purchased in rolls of a certain weight, and any width. When sold in sheet form they are usually sold by number of sheets; when sold in roll form, by weight. An inspection of the trade catalogue or letters of inquiry to any of the manufacturing concerns will bring further information if desired.

The standard size of a detailed sheet is 24X36 inches. Inside of this are drawn two borders each 1/2 inch from the other. In the lower right-hand corner is the place for the title. The size of this block is 4X5 1/2 inches. The 24X 36-inch size is the outside dimension of the brown paper or detailed sheet. The 23X35 inch, which is the size of the first border line, is the line upon which the blue prints are cut. The second border line is the real border line of the drawing, and remains upon the blue print. Fig. 5 indicates the dimensions indicated above.

Fig. 5. Standard Detail Sheet with Dimensions

Fig. 5. Standard Detail Sheet with Dimensions.

Tracing Cloth. Tracing cloth is used on account of the fact that the prints may be made from it and, therefore, any number of duplicate copies may be made available for distribution to the various departments. The drawings should be made upon the rough side of the cloth since this takes the pencil mark and also the ink better than does the smooth side. The rough side is also of a great advantage when it comes to reproducing the figure by photography. In order to make the ink take readily upon the tracing cloth and flow easily, the cloth should first be cleaned by rubbing over with powdered chalk or wiping it off with gasoline. This removes all trace of grease. Before placing the tracing cloth upon the drawing, the pink border or edge which appears upon the cloth should be torn off. If this is not done the sheet will be affected unevenly by changes in temperature, and dampness will cause the cloth to wrinkle up on account of the fact that the border is not affected by dampness and the remainder of the cloth is. This will make it difficult for the draftsman to complete his drawing in good form in case he has let it lay over for a considerable time, since the lines which he made at first will be moved from their original position by the wrinkled condition of the sheet. In case it has been forgotten to tear off this border and the sheet becomes wrinkled it is advisable totear off the border and leave the sheet until it becomes straightened out before further drafting is done.