The Link-Cutter

The link-cutting machine consists of one fixed lower cutting-blade and one sliding upper cutting-blade, which slides in a groove and is operated by belt and pulley gears. The spirals are fed into the cutting-blades from the left side of the cutter and held in such a manner that the iron is cut at an angle of 60 degrees with the diameter of the rod, each cut releasing one link, wound and scrafed ready for welding, and at the rate of one cut every second, or 36,000 links per day.

The Welding Machine

The power-hammer on which the chain is now welded is shown in Fig. 231 and represents the results of years of experience and trial. When the idea of welding the links of a chain by means of dies instead of by blows of hand-hammers was first conceived, a foot-power hammer was attached to the anvil, the hammer being hinged on the opposite side of the anvil from the smith and so arranged that by kicks on a foot-treadle the smith could swing the hammer-arm down to meet the face of the anvil. In the lower face of the hammer-arm was attached the upper die, and on the face of the anvil. In the lower face of the hammer-arm was attached the upper die, and on the face of the anvil was attached the lower die, the result being a smooth finish superior to that of a hammer-welded link. This was a big step in the right direction, but it was soon found that on large sizes of chain the labor of operating the hammer-arm by foot-power was too great and the present well-known type of power-operated hammer was devised to obviate this difficulty. The power for operating this type is conveyed to a pulley on the hammer-base by means of a belt from the shafting of the shop, arranged to give the hammer a speed of about 120 strokes per minute. The weight of the hammer-arm is in its head, and the force of its blow is due both to gravity and to the pulling-power exerted by a powerful spring. The machine is so arranged that when not in use the arm is raised about a foot from the face of the anvil and held

there by a catch, so that when this catch is removed by a pressure on the foot-treadle, the hammer will fall heavily on the face of the anvil. The pulley on the hammer-base operates a short shaft carrying an elliptical cam, and is so arranged that when the hammer-arm is caught and held up from the face of the anvil the cam will not meet the base of the arm, but when the arm has been released and descends on the anvil the base

FIG. 231.-The welding-hammer.

of the arm is brought within reach of the rotating cam, which strikes the base of the arm and raises the arm about a foot from the anvil, when further rotation of the cam releases the arm and permits it to fall again. This operation continues until the link has been welded, when, by releasing the foottreadle the arm is caught and held up until another link is ready to weld. By means of this hammer 1,000 pounds

of %-inch chain can be welded in one day, equivalent to 124 feet, or 626 links, being four times the daily production under the old hand process.

In regard to the dies used, the lower die consists of a block of steel cut away until a small rounded projection is left which will just fit inside the end of the link, while the upper die is a block of steel hollowed out so that it will just fit over the outside of the end of the link, the space between the two dies being just the size of the end of the link which is to be welded. These dies are fitted in spaces left in the face of the hammer-head, and the face of the anvil, so that different size dies can be used on the same power-hammer, according to the size chain that is to be welded.

The Process of Welding

The smith selects from the several links in the glowing bed of coke in the furnace one that has reached the weldingheat, and hooking it through the link last welded, places the open end of the link over the lower die. Pressure on the foot-treadle releases the hammer-arm and the impact of the blow forces the scrafed ends closely together and welds the link, the dies reducing the body of the weld to the same size as the rest of the link and giving the weld a smooth, finished appearance, superior to a hammer-welded chain. About ten blows of the hammer-arm are required to make and finish the weld, the interval between the blows of the arm being utilized by the smith to turn the link over and back on the lower die and to lightly tap the weld with his hand-hammer, thus giving the proper working necessary to secure a perfect weld.

The use of these three important machines has completely revolutionized the process of chain manufacture, the result not only being increased production, but also a much better grade of chain at a greatly reduced cost.

CHAPTER VIII

FORGING MACHINE, STEAM-HAMMER, BULLDOZER, AND SWAGING MACHINE METHODS AND

PROCESSES

Handy Bulldozer Appurtenances

THE bulldozer, or bending-machine, is at present found in almost every car, railroad, bridge, and agricultural shop in the country, and as a time-saver and all-around tool for wroughtiron work it stands preeminent. Long experience with this machine and with the varied methods used in different shops have given opportunity to judge of the easiest and best meth-. ods for doing work on it.

A back plate (Fig. 1, of whole Fig. 232) is dispensed with in many shops using this machine, but why, unless it is ignorance of its utility, is unknown, as it is indispensable. Having introduced it in several shops, it has always been retained, and the wonder has been how they got along without it before. It keeps the work straight, saves a great deal of gray iron, and it is much easier to fasten the forms to than the bed of the machine.

By making a divided apron, or flat part, as in Fig. 2, and casting a lug on the bottom, see Fig. 3, its usefulness is increased and the plate is lightened for easier handling. The plate should be made plenty wide enough to take in the longest work done on the machine and the face and apron should be planed perfectly true. A depressed fillet at A, Fig. 2, allows a former to always go snug against the back. Two bolt slots in the back are better than having to drill new holes to fasten the forms. The holes in the forms can be cored to suit, or drilled as desired.

The plate on the ram head is shown in Fig. 4. It should have tongues cast to fit the crosshead firmly, so that there will