These ingots are much too thick (+-1cm) to do anything with, so they must be sent through a rolling mill for make them flat, and reduce the width of the metal. This part of the process takes the longest if you have a manual rolling mill like me, and it means HARD LABOR!
The ingot is placed between 2 rollers, and the crank is turned to pull the metal through to the other side. The spindle at the top is adjusted after every pass the silver takes through the rollers to narrow the gap and making the silver a little bit thinner the next time it goes through.
Before we go any further, here is a quick note on Annealing:
Annealing – Annealing, in metallurgy and materials science, is a heat treatment that alters the physical and sometimes chemical properties of a material to increase its ductility and reduce its hardness, making it more workable. – Wikipedia
After a couple of passes through the rolling mill rollers, the Sterling ingot or plate, becomes to hard to go any thinner, and it must be annealed to make it softer in order to work with it again. Sterling silver anneals between 750°C to 760°C.
These ingots were passed through my roller dozens of times, and were annealed half a dozen more.