The Belgian Mill
The first bars and rods were rolled in the old two-high mill, where, after each pass they were pulled back over the top roll and inserted into the next groove by the roller as is usual with the two-high mill. Then along came the three-high mill which probably resulted in greater advantage to rod rolling than to other lines, important, even, as it was to them.
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.
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.
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.