1. What is the weight of a bar of flat iron 1 foot long, 2½ inches wide and ¾ inch thick ? Ans. 6.25 pounds.
2. What is the weight of a bar of flat iron 4 feet 6 inches long, 2 inches wide and 1 inch thick? Ans. 30 pounds.
3. What is the weight or a bar of flat iron ½ inch thick, 3 inches wide and 14 feet long. Ans. 70 pounds.
The weight of any piece of wrought iron can be calculated in the same way as directed for cast iron in "Foundry Work," page 32, except that the constant coefficient used is .2777 instead of .2607. The rule thus becomes.
Multiply the volume of the piece of iron in cubic inches by £777 or in the case of mild steel multiply by 3833.
1. What is the weight of a piece of wrought iron containing 1,824 cubic inches? Ans. 367.67 pounds.
2. What is the weight of a wrought iron plate ¾ inch thick and 2 feet square? Ans. 120 pounds (nearly).
3. What is the weight of a plate of wrought iron \ inch thick, and in the shape of an equilateral triangle whose sides have a length of 24 inches ? Ans, 34,64 pounds.
In the actual work of the blacksmith shop one of the simplest jobs is the making of an ordinary staple, Fig. 45. The first stages of this are shown at a and b of Fig. 46. The iron is first cut to a suitable length a. It is then heated first at one end then at the other and pointed as at b. This pointing is done on the flat face of the anvil while the metal is hot. It should be noted that the pointing draws the metal out somewhat. Hence the piece is longer in the condition b than it was in the condition a. Allowance for this must be made in cutting off the metal. After pointing, the iron is bent to its final shape over the horn of the anvil. One end is lipid between the jaws of a pair of flat tongs as in Fig. 47, while the other end is struck by a hammer as shown.
If the iron is 3/8 inch in diameter or less it may be bent sold. If more than 3/8 inch in diameter it is well to heat it for more than half its length and bend while still hot after pointing. When needed in large quantities staples of this kind are made complete by machinery.
U bolts, Fig. 48, are made in the same way. The threads are cut while the iron is still straight.
In drawing iron there is always a little waste due to the formation of scale and the action of the fuel. This is usually so smail in amount that it can be neglected. Where it is possible to trim the finished forging, the amount of metal originally cut off is more than .sufficient to allow for the drawing or Upsetting. In the case of the staple. Fig. 45, the exact allowance should be made. If it is not so made, the smith can vary the sharpness of the pointing. The more gradual the. taper the longer the staple. As there is no appreciable loss of metal the weight and therefore, the bulk of the material maybe considered to be the same before and after drawing or upsetting.
1. What will be the final length of a bar of round iron 1½ inch in diameter and 6 feet long, 18 inches of which is to be drawn down to a diameter of | inch.
Ans. 10 feet 6 inches.
2. A staple is to be made of $ inch round iron ; it is to be 13 inches long over all and the taper is to extend back for 2½ inches from the ends. What length of metal must be cut from the bar in order to make it? Ans. 9 3/8 inches.
3. It is desired to have a square shank having a side of 1 inch and a length of 6 inches on the end of a rod 1¼ inches in diameter. What length of the round metal will be required for the square shank?
Ans. 4.89 inches. 4. A head is to be upset on the end of a rod 1 inch in diameter. This head is to be cylindrical, ¾ inch long and 1| incites in diameter. What length of 1 inch rod must be allowed to make the head ? Ans. 2.3 inches.