These are the bolts for the porthole, but because they are zinc coated they are too silver, I was going to sand blast them and then Kurust them to get a darker finish.
I decided that the sand blast/Kurust process was a bit too long winded, then I remembered that it was possible to heat up the bolts. Heating up the bolts to a nice yellow heat burns off the coating and leaves them darker. The oxy acetaline torch was perfect for this process.
I placed the bronze face into the porthole to see the effect, it isn't bolted in yet as the two cast iron halves need to be welded together, but the bolts match the iron exactly.