Hi Gav
Yes it's made from silver steel which is a high carbon steel available in metric & imperial sizes and is ground finish and readily available. The bar is in it's annealed state and you manufacture your required tool then heat it to cherry red and quench, then polish the tool and apply heat to the end of the shaft and you will see the polished surface change to a straw color as this works it's way to the cutting part of the tool quench in cold water and that's it tempered.

Looking @ your drawing that profile is situated in the sliding part of the jobby that the mould goes into,is that correct ?