At the top or bottom of a sheet, such general directions as apply to the work as a whole are given, as "Rivets, in. dials. except noted". "Open holes 1g- in. dram., except as noted". "Paint, one coat Superior graphite".
The student should carefully study all the dimensions in con nection with the cuts, and should thoroughly understand these and the problems before starting on the subject of detailing from a plan. Note at each side of a beam sketch, are figures preceded by a plus or minus sign. These measurements denote the distance from the end of the beam in the sketch to the center of the beam or column or other member to which it connects, or the distance from face of the wall to end of the beam. These figures are not necessary for the complete detailing of the beam, but they are of great assistance in checking the drawings, as they show just how much is to be added to or substracted from the measurements on the setting plan to give the length of piece as detailed.
1. Practice making freehand letters of the style shown on the details, both capitals and small letters. Make the letters in each word of uniform size, also practice making letters of different sizes. This is important as it is often necessary on shop drawings to put a note on a part of the drawing where space is very limited, and the writing must be small. Make a copy of the alphabet (capitals and small letters) and a copy of the numerals; also print the following in three sizes: "All bearing plates to be faced."
One size to have a height of in. for the small letters, another size k in. high, and the third size i in. high.
2. Make a shop drawing of a 6-in. I-beam, 6 ft. long, with two holes for -R--in. rivets in top flange at each end, and 11 in. from the ends. Also make holes for /-in. rivets spaced 6 in. apart in the middle of the web for the full length. The end holes should be 3 in. from the end of the beam.
In this example, the only work specified is the punching of the rivet holes, and therefore, as no other work is required, the shop drawing will consist only of the outlines of the beam, with the rivet holes located on the same, and the spacing of the rivets shown by dimension lines, as indicated in Fig. 196.
3. Given a 20-in., 65-1k. I-beam 22 ft long, framed into a 20-in., 80-lb. I-beam. The 20-in., 65-lb. I-beam has a 15-in., 42-lb. I-beam framed into each side every 5 ft. 6 in. with its top flush with the 20-in. I-beam. If the reaction of each 15-in. I-beam is 7 tons, state the number of rivets required for the connections of the 20-in., 65-lb. beam and for the connection of the 15-in. beam, using 9,000 pounds for shear and 18,000 pounds for bearing.
4. Make a shop detail of the 20-in., 65-lb. beam in the above problem, using standard connections.