By suggestion of my nephew, I decided to make my own hallmark stamp. I think anybody that makes things should have a mark of some sort, to identify them as the maker. I have used a derivation of my initials to mark some items I've made in the past using ink (most items bear no mark); time to try something permanent and carve it from steel, in stamp form! I wanted it to be hard and durable, so I selected a rarely used tool for the job, a hex key socket fit the bill nicely (Tool steel is best, I think). First I needed a pattern, so I printed a honeycomb pattern I found on line, that I then scaled to fit my 1/2" hex key. I then made my mark a number of times to find a pattern that I found suitable, and would use five of the six points available on the key. I then cut it out, applied some super-glue and clamped it tightly in the vise to dry. While it was drying I heated the end of the key to beyond its' magnetic point (transformation temperature), with a propane torch supported inside a sort of furnace made from fiberglass insulation that had the paper stripped from the outside (be very careful doing things like this at home, though the fiberglass does not burn it will melt if the flame is impinging on it and there are noxious fumes released as well!) This was done with an exhaust fan taking fumes outdoors. The steel needs to be heated until a magnet will not stick to it (around 1600 Deg F depending on the alloy used), then the piece was wrapped in the fiberglass enclosure to ensure it cooled very slowly to effectively anneal it. After annealing it was checked with a file, to see if it was soft enough to cut with the file. Later pictures of re-hardening the piece are the same as picture would be of annealing. (The pictures don't show much, in this case the words will tell you more about what is taking place).

I like the idea of modifying the socket to hold and align the punch.

spylock1 year ago

I believe its "straw"the real golden color after it gets cherry.

Some nice work. How do you tell if you have got the metal to "transition temperature"? I gather it's usually identified by colour. What colour is it?
djokimaki (author)  Dream Dragon2 years ago
The transformation in steel is when the steel goes from being magnetic to non-magnetic. As I don't have reliable instrumentation, I just use a magnet to check when it will no longer attract the steel. Regards, and thanks for the visit!
The metal loses its magnetic properties at that temperature. As you heat it, keep touching the metal with a magnet to see if it sticks. When the metal not longer attracts the magnet, you've reached the temperature you want.