Page:Sheet Metal Drafting.djvu/126

112 {|
 * Diameter in Inches|||Height in Inches|||Approximate Capacity
 * 24|||36||72 gallons
 * 20|||26||34 "
 * 18|||26||28 "
 * 17½|||26||24½ "
 * 14|||26||16 "
 * }
 * 18|||26||28 "
 * 17½|||26||24½ "
 * 14|||26||16 "
 * }
 * 14|||26||16 "
 * }
 * }

Type of Hoop.—There are several types of hoops that can be obtained from the jobber. Figure 156 gives a full size cross section of the one generally used.

Blank for Body.—The body of the ash barrel is made from No. 24 galvanized steel. The top and bottom hoops fit into the barrel one-half of their entire width, Fig. 157; therefore, the body blank must be ⅞in.×2 or 1¾ in. less than the total height of the barrel. This would make the blank 24¼ in. wide, but in order to use the sheet metal as it comes from the mill the total height would be reduced to 25¾ in., Fig. 157, and stock size sheets 24 in. wide used to make the body. The riveted seam is somewhat stronger, but since the lock seam can be placed under a slat and protected, it is generally used because it can be made more cheaply.

Weight of Bottom.—The bottom of the barrel should be at least four gages heavier than the sides.

Type of Slat.—Figure 158 shows two types of slats in common use. The three-rib slat is made of No. 24 galvanized steel by means of special machinery. The single-rib slat may be made on an ordinary cornice brake and used with or without the wooden core.

Sizes of Rivets.—In riveting the slats to the barrel, the rivets must pass through two thicknesses of No. 24 gage. This will require a 2½ lb. rivet. The rivets for the upper hoop must pass through one thickness of No. 24 gage iron and $$\scriptstyle\frac{3}{32}$$ in. of steel in the hoop. This will require a 6 lb. rivet. The rivets for the bottom hoop must pass through one thickness of No. 24 gage (the body), one thickness of No. 20 gage (the bottom), and $$\scriptstyle\frac{2}{32}$$ in. of steel in the hoop. This will require an 8 lb. rivet.

Drawing the Section.—A section. Fig. 157, showing the hoops, body, and bottom in their proper positions, should be drawn.