My son would like to try some forging. I have some springs-probably5160-in 1/4" and 3/8-1/2" thick. About 2" wide. How large a piece do you think he should start with?(length) Probably bowie-thpe knife, knowing him!! Or should we buy stock from a supplier? What thickness/length? I'm anticipating some thinning, etc. And a fair amount thrown in the "recyle" file. 1075? 1095? Other?