[Illustration]
Most chains are made by hand, especially those used for the purpose of
lifting heavy loads. Small chains, where no special strain is called
for, are welded by electricity. There are special factories for the
making of chains. Most of these factories have rolling mills attached.
The material is here rolled out to suit the different size chains that
are made. Machinery forms the bars of iron into special shapes the size
of the links. These in turn are cut by machinery. These links are all
of the same size and are cut off on an angle, thus making the scarf.
They are taken by the workmen, the ends lapped over slightly, then put
into the fire and welded. Within the last few years the Navy Department
has taken up the method of welding the large anchor chains by machinery.
_Stock:_ 3/8 in. round, 6 ins. long.
[Illustration]
[Illustration: Scarf for chain welding]
[Illustration: Link ready to weld the end]
_Directions:_ The drawing shows the size of each link in this chain.
Heat the 6-in. piece in the middle. Place it on the horn of the anvil
and bend it U-shaped, as you did the piece for the staple. (See
articles in welding for chains.) The two ends are the same length.
This is perhaps the only weld that is made without upsetting. When the
scarfs are made like the drawing, bend the ends so that the scarfs
overlap. Now it is ready for welding. Place the link in the fire. Be
careful to have the link well covered both above and below with hot
coals. Let there be just enough blast to increase the heat of the fire.
In a little while the sparks will flow up from the iron. At this time
the link should be turned upside down in the fire without changing its
position. The hottest part of the fire being underneath, the iron will
heat there quickest. This turning it upside down finally brings all the
parts to be welded in the hottest part of the fire. When these iron
sparks begin to show, it is time to take the piece out. Place it on the
anvil and lightly tap upon the joint. The iron is very soft on account
of the intense heat and if the blows are too heavy the iron will
flatten out until it is too thin. In that case it would be impossible
to finish the piece and make the weld the size it should be when done.
If you examine the links of any chain you will have difficulty to find
the welded end. The process of welding is not easy at first, but a
few trials with the heating of the iron and handling the tools at the
critical moment will prove encouraging. Chains are usually made by
making first one link, then putting the stock for the next link into
the first, before bending the second end.
All hooks, swivels, or shackles are put on the chain when made, in the
same way that you add a link in order to lengthen the chain.