Non-technical chats on iron and steel, and their application to modern industrySpring, La Verne W. (La Verne Ward)
History
Non-technical chats on iron and steel, and their application to modern industry
Spring, La Verne W. (La Verne Ward)
Iron; Steel
But long, thin bars or rods are quite pliable when at white or rolling
heat and the “catcher” soon discovered a way by which he could save time
and push up his tonnage. He skillfully caught the forward end of the bar
as it came through, and, giving it a quarter twist, he inserted it in
the proper return groove without waiting for the whole bar to run
through to his side before starting it on its return journey. This, of
course, was easily possible with the slow speeds then used.
Naturally the rod coming through from one side and going back to the
other formed a loop.
The roller, at the front, was not slow in discovering that on long rods
he could do the same thing, so rods were soon regularly going through
three or more passes at the same time.
[Illustration:
WIRE DRAWING OF 350 YEARS AGO
]
It was soon found out that it was better to use a second set of rolls
placed end to end with the first for the third and subsequent passes as
the roller had hardly room or time to loop the rod on the return and
start his next one. This second set of rolls was connected on the same
shaft and therefore made to run at the same speed as the first. It
worked out that by use of such extra sets of rolls and an additional
helper or two the same long rods could be running through as many as six
or seven passes at once with a great saving in time.
As it came from the final pass the forward end of the finished rod was
seized in a pair of tongs by a boy who ran with it away from the rolls,
stretching it out along the floor to cool. As the various sets of rolls
were connected on the same driving shaft and revolved at the same speed,
the loops which were formed between passes continually grew longer.
Here, too, boys with iron hooks were useful in controlling the loops.
Later it was found advisable to have each succeeding mill speeded enough
to take the rod as the preceding pair of rolls delivered it; then the
loops remained of approximately constant length.
[Illustration:
PLAN OF A MODERN LOOPING MILL (THE GARRETT MILL)
]
To push production the mill was run faster and faster. As longer rods
were rolled, a hand-operated reel was devised to which the boy attached
the forward end of the rod while another turned the reel. But the speed
of the mill was limited mainly because of the slow reel and the awkward
method of getting the rod attached to it.
The Bedson Continuous Mill
About 1867 George Bedson of England, invented the first “continuous”
mill.
Public-domain text, read in full here on John Shaqi.
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