136 JOHN O'DONNELL 



Hinges, for instance, are made from heavy bands and not 

 from plates. The difference might appear immaterial at 

 first glance, but is vital to the hinge maker, since the band 

 comes from the rolling mill of the proper width and requires 

 but one operation of shearing per blank. Many similar arti- 

 cles are made from bands with a surprisingly small amount 

 of manipulation, because the steel rolling mill has already 

 given the material two of its required dimensions. 



