This section is from the book "The Manufacture Of Boots And Shoes: Being A Modern Treatise Of All The Processes Of Making And Manufacturing Footgear", by F. Y. Golding. Also available from Amazon: The Manufacture Of Boots And Shoes.
Whatever system is adopted, the closed seams should be well rubbed down so as to occupy as little space as possible, and also to present as little irregularity to the foot of the wearer. To this purpose seam-rubbers are used.
One type of seam-rubber consists of a cylindrical bar of iron 16 in. long, and about 11/2 in. in diameter. Attached to one end of this bar is a handle, by which it can be rotated. The other end of this bar is fastened to a collar, which allows it to revolve. The collar is fastened to a pedestal, which also gives origin to an arm of the shape of the part required to rub down.
Machines are also used for this purpose, and either the "Rapid" or "Union" are good makes. The latter also ploughs or cuts out a welt if welted, as well as rubs down the seam. Fig. 190 shows a seam-rubber.