Outside diam. in inches. Thickness of metal. 112 14 15 1 15 15 114 Tons. Tons. Tons. Tons. Tons. Tons. Tons. Tons. Tons. Safe load on standard wrought iron pipe used as columns. = 6. The table above gives price per keg of all varieties of nailsthe rates are computed on the price of a keg of from 20 to 60 penny as a base-to which must be added the advance rate for the smaller sizes as shown. The wholesale base for wire nails is $1.70 and for cut nails, $1.60. EXAMPLE. To determine price of a keg of 8 penny wire nails : To the base of $1.70 add the advance rate of 10c., giving $1.80 the price per keg. Cut Nails vs. Wire Nails. A series of interesting experiments was recently made at the U. S. Arsenal at Watertown to decide upon the relative merits of cut and wire nails. At the first test the size of the cut nails ranged from 11⁄2' nails to 6" spike, forty penny and sixty penny, and ranging in number per pound from six to seventeen. The wire nails were of approximately the same size and weight. The nails of the respective sizes were driven into a spruce plank to a uniform depth-the larger spike to four inches. The total weight of the nails differed but two grammes, the wire nails weighing 214 and the cut nails, 212 grammes. In the first test a force of 733 pounds was required to draw the wire nail and 836 pounds for the cut nail. The second wire nail was drawn with force of 673 pounds, while 742 pounds were required for the cut nail. The third wire nail required 675 and cut nail, 8C4 pounds. The fourth wire nail, 594 and the cut nail, 964 pounds. The fifth and sixth nails were drawn at nearly the same ratio. The seventh wire nail was drawn at 879 pounds, while it required 1,200 pounds for the cut nail. Care was taken to have the tests fairly made and accurate. The results thus obtained would indicate that cut nails are superior to wire nails for work when dependence is placed on nails to hold it together. Slating. Slating is calculated by the "Square," meaning the area of 100 square feet, and is usually laid in 3 thicknesses, that is, the third laps over the first three inches, with the second one between. To ascertain the number of slates of a given size, required per square, substract 3 inches from the length of the slate, multiply the remainder by the width and divide by 2 (this will give the number of square inches covered per slate); then divide 14,400 (the number of square inches contained in a square) by the number found as above, and the result will be the number of slates required to cover a square. The following table gives the number of slates per square for the usual stock sizes: The weight of slate per cubic foot is about 175 lbs., or, per square foot of the usual thicknesses, as follows: The weight of slating will depend on the size used. in. For example a 10 X 18 slate = 1.25 sq. ft. of surface; if thick, its weight will be 1.25 × 2.73 = 3.41 lbs., and as there are 192 slates in a square, the weight of a square will be 192 × 3.41 = 654 lbs. or 6.54 lbs. per square foot. Scaffolding with Round Spars. In erecting a scaffolding by this method, the uprights and cross-pieces supporting the platform do not require to be nailed or bolted together. The effect of the wind on a nailed structure is to loosen the joints and thus reduce its strength. Rain and dampness will cause the wood to swell, which, afterward shrinking, will cause loosening and splitting at the joints. Nailed scaffolding is always more or less injured and broken during removal, after a job is completed, and can seldom be used more |