TABLE, EXHIBITING THE EXPERIMENT AL STRENGTH Of various species of Timber opposed to a transverse strain. TABLE, Exhibiting the number of Threads to an inch in V.-thread Screws. The depth of the threads should not be less than half their pitch. The diameter of a screw, to work in the teeth of a wheel, should be such that the angle of the threads does not exceed 100. Friction constitutes the whole efficacy of the screw. TABLE Of the sizes of Nuts, equal in strength to their Bolts. NOTE. The depth of the head should equal the diameter of the bolt; the depth of the nut should exceed it, in the proportion o. 3 or 10 to 8. Of Change Wheels for Screw Cutting, the leading screw being inch pitch, or containing 2 threads in an inch. COPPER. To find the Weight of Cast Copper. Rule.-Ascertain the number of cubic inches in the piece, and multiply them by 317 (for copper plate multiply by 321), and the product will be the weight in avoirdupois pounds. Example.-What is the weight of a piece of cast copper 1 inch thick and 20 inches square; and what of copper plate inch thick and 10 inches square? 20×20×1=400 and 400 × 317=126·80 lbs. And 10×10 x = 50" 50X321 160.50 lbs. BRASS. To find the Weight of Brass Castings. Rule. Find the number of cubic inches in the piece, and multiply them by 311, the product will be the weight in avoirdupois pounds. Example.-Required the weight of a piece of casting, containing 117 cubic inches. 117 × 311 36.378 lbs. LEAD To find the Weight of Lead. Rule.-Ascertain by calculation, the number of cubic inches it contains, and multiply them by 41, and the product will be the weight in avoirdupois pounds. Example.--Required the weight of a leaden pipe 18 feet long, 3 inches bore in diameter, and inch thick. By Areas of Circles and Rules in Mensuration, &c. Area of 4 inch = 12.566 66 ❝ 3 inch 7.068 18 feet 216 inches. 5 498x216-1187.568 area of ring 41 486 90288 lbs TABLE, Showing the Size of Cables and Anchors, proportioned to the Tonnage of Vessels. The proof in the U. S. Naval Service, is about 12 per cent. less than the above. TABLE, Showing what Weight a Good Hemp Cable will bear with Safety. Rule.-Multiply the square of the circumference, in inches, by 120, and the product is the weight the cable will bear, in pounds, with safety. |