The surplus metal which has protruded between the lower and upper dies resembles a fin or web; this has caused the forging to be mistaken for a casting of iron, because the fin resembles in no small degree the gate or connection between castings when moulded. This fin of metal is trimmed off from the forging by means of another machine, called the trimming press, to which are fitted dies for this purpose. Experts in the trade say that no “hand-made” forgings or “castings” can ever wholly take the place of drop forgings in bicycle construction. Drop-forging manufacturers say that hand-made forgings are obsolete, owing to the enormous cost of manufacture.
WOLFF-AMERICAN
LAPPED JOINT.
Malleable iron castings, or steel castings, are used by some of the makers, but entirely sub rosa. They are apt to be full of blow holes and other defects and not at all reliable, and the maker of high-grade bicycles who advertises that he uses such castings in his bicycles will soon find himself out of the market with his product entirely on his hands.
SHEET STEEL PARTS.
Sheet steel parts, such as are used in bicycle construction, consisting of cups, brackets, crown heads, etc., when made from sheet metal are stamped in presses from dies. These presses stand about 6 feet high, 2½ feet square, and weigh about 4,000 pounds. They are operated by a large driving pulley and belt, the motion being given by means of an automatic clutch. They can be placed on the floor of any building, owing to the fact that they do not have the jar that is incident to “drop” press work.
THE CLEVELAND.