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.
The blanks are first cut out of cold sheet steel, thereby avoiding the expense of heating them. They are then placed between dies which have been previously made to form the required design and shape, but are not as a rule completely struck up or formed at one operation, the minimum number of operations necessary to form the complete article being one or two, and the maximum being from five to seven. The parts are often annealed between the operations, as the pressure has a tendency to harden the metal.
REMINGTON
FLUSH JOINT.
The makers and users of sheet steel parts claim for them as advantages over drop forgings that they are of uniform size, shape and gauge; that they weigh less; that there is but little waste of material, and that as many as ten thousand operations can be done by one operator in a day. Of course, the cost of production is thus made lower as compared with the cost of production of drop forgings, which require a large amount of machining on lathes and other milling machines, necessarily slow in operation. The makers of these stamped form-drawn parts claim that through the largely increased use of their goods American makers have been able to produce lighter bicycles than they were formerly able to produce with the use of drop forgings for their connections, that the popularity of the bicycle in this country is due to the present popular prices at which they are sold, and that these popular prices are largely due to the low cost of sheet metal parts. They also claim that after the sheet metal parts and the tubes of the bicycle are brazed together, they then form one continuous piece, to all intents and purposes as good as if a solid drop forging were used. The average thickness of the sheet steel used in making these stampings is from 1⁄16 to ⅛ of an inch. Some very remarkable forms are produced in steel stampings, notably a crank-hanger of 2 inches in diameter, having two projections or lugs to carry the rear forks, and the two outer projections or lugs to carry the large lower main tubes and the large diagonal stay of the bicycle frame.