RULES FOR SHOP DRAWINGS. 



899 



t it U > Lconardt & Co.'s Ball-Pointed No. 5i6F; for all other lettering Hunt Pen Co.'g extra fine Shot 

 Point, No. 512. No pen finer than Gillott's No. 303 should be used. Light pencil guide lines 

 Mull he drawn for all lettering. All tracings shall be made on the dull side of the tracing cloth. 

 Kr.i-urcs shall be made with soft rubber pencil eraser and a metal shield. Rubber erasers con- 

 taining sand destroy the surface of the cloth and make it difficult to ink over the erased spot. 

 The use of knives or steel erasers will not be permitted. Tracings shall be cleaned with a very 

 soft rubber eraser, and not with gasolene or benzine, which destroy the finish of the tracing cloth. 

 All liiu-s shall preferably be made with black India ink; full lines to represent members, dash and 

 dot to represent center lines, and dotted lines (or full light black lines) to represent dimension 

 lines. If permitted by the chief draftsman red ink may be used for dimension and center lines. 

 The ends of dimension lines shall, however, always be indicated by arrows made with black 

 ink. 



Conventional Signs. Conventional signs for rivets are shown in Fig. 10. Countersunk 

 rivets project J in.; if less height of rivets is required, drawings shall specify that they are to be 

 chipped, or the maximum projection may be specified. Flattened heads project f in. to iV in -l 

 if less height of heads is required, they shall be countersunk. Metals in section shall be shown 

 as in Fig. n. Standards for rivets and riveting are given in Part II, which see. 



Marking System. A shipping mark shall be given to each member in the structure, and no 

 dissimilar pieces shall have the same mark. The marks shall consist of capital letters and num- 

 erals, or numerals only; no small letters shall be used except when sub-marking becomes absolutely 

 necessary. The letters R and L shall be used only to designate "right" and "left." Never use 

 the work "marked" in abbreviated form in front of the letter, for example say, 3 Floorbeams G4, 

 and not, 3 Floorbeams, Mk. G4. Whenever a structure is divided up into different contracts care 

 should be taken not to duplicate shipping marks. Pieces which are to be shipped bolted on a 



5teel 5teel Cast Iron Cast Steel Bronze 



FIG. ii. CONVENTIONAL SIGNS FOR METALS. 



member shall also have a separate mark, in order to identify them should they for some reason 

 or another become detached from the main member. The plans shall specify which pieces are 

 to be bolted on for shipment, and the necessary bolts shall be billed. For standard marking 

 system for a truss bridge, see Fig. 7. 



A system of assembling marks shall be established for all small pieces in a structure which 

 repeat themselves in great numbers. These marks shall consist of small letters and numerals 

 or numerals only; no capital letters shall be used; avoid prime and sub-marks, such as M a f . Pieces 

 that have the same assembling mark must be alike in every respect; same section, length, cutting 

 and punching, etc. 



Shop Bills. Shop bills shall be written on special forms provided for the purpose. When 

 the bills appear on the drawings as well, they shall either be placed close to the member to which 

 they belong or on the right hand side of the sheet. When the drawings do not contain any shop 

 bills, these shall be so written that each sheet can have its bill attached to it if desired; one page of 

 shop bills shall not contain bills for two sheets of drawings. In large structures which are sub- 

 divided into shipments of suitable size, both mill and shop bills must be written separately for 

 each shipment. In writing the shop bill bear in mind that it shall serve as a guide for the laying 

 out and assembling of the member, besides being a list of the material required. For this reason 

 members which are radically different as to material shall not be bunched in the same shop bill, 

 neither shall pieces which have different marks be bunched in the same item, even if the material 



