Page:Sheet Metal Drafting.djvu/157

Problem 34
REGISTER BOXES

64. Register Boxes.—Register boxes are generally made from 1 C coke tin, commonly called by the trade "furnace pipe tin." The tin box must be made to fit the body size of the register. An allowance is generally made to assure an easy "fit" between the body of the register and the box. This allowance varies with the sizes of the registers as follows:

Size of Register Body.	Dimension of Box.	Depth of Box.
Not wider than  4 in., any length	Add ¼ in. to each dimension of body	4 in.
Not wider than  5 in., any length	Add $\scriptstyle {\frac {5}{16}}$ in. to each dimension of body	4 in.
Not wider than  7 in., any length	Add $\scriptstyle {\frac {9}{16}}$ in. to each dimension of body	4 in.
Not wider than  8 in., any length	Add ⅝ in. to each dimension of body	4 in.
Not wider than 11 in., any length	Add $\scriptstyle {\frac {11}{16}}$ in. to each dimension of body	5 in.
Not wider than 12 in., any length	Add ¾ in. to each dimension of body	5 in.
Not wider than 18 in., any length	Add ⅞ in. to each dimension of body	6 in.
Wider than 18 in., any length	Add $\scriptstyle {\frac {15}{16}}$ in. to each dimension of body	6 in to 8 in.

Figures 193 and 194 show end and side elevations of a register box for a 9 in.×12 in. register. According to the table, the dimensions of the top will be $\scriptstyle {9{\frac {11}{16}}}$ in.×$\scriptstyle {12{\frac {11}{16}}}$ in.

End Elevation.—The end elevation is drawn according to the dimensions given in Fig. 193. A half-profile of the "neck" is drawn and divided into equal spaces and each space numbered. The neck is joined to the box by a "bead and flange" joint. The corners of the elevation are numbered 1, A, 2, 3, B, and 4 as shown.

Side Elevation.—A side elevation should be drawn according to the dimensions given in Fig. 194. The points 5, C, 6, 7, D, and 8 are numbered as shown.

Pattern of Ends.—First, any horizontal straight line (line 2–3 of