Blacksmithing Custom Coins: From Steel Block to Finished Product
0:00:02 Introduction to Coin Making: The goal is set to forge custom coins using closed-die forging techniques with a steam hammer, which requires creating a custom steel die first.
0:01:07 Die Material Selection & Forging: P20 tool steel is chosen for the die block. The raw steel block is forged into a workable shape using the Massey steam hammer.
0:02:10 Failed Annealing Attempt: An initial attempt at annealing the P20 steel by slow cooling in the forge fails, leaving the block too hard (tested at 40 Rockwell C) for the necessary machining and carving.
0:03:46 Proper Annealing Process: A controlled annealing cycle is performed in a kiln (heating to 780°C, cooling at 4°C/hour), taking 36 hours but successfully softening the steel to a workable 3 Rockwell C.
0:04:50 Machining the Die Impression: The softened block is re-machined to clean it up. The negative coin impression (45mm diameter, 4.5mm deep) is machined, and a reversed/mirrored touchmark design ("S") is meticulously carved into the die face.
0:10:00 Die Mounting & Hardening: A temporary bracket system is fabricated to mount the bottom die in the steam hammer. The completed die is then hardened through heat treatment and tempering.
0:11:51 Preparing Coin Material (Pucks): Steel discs (pucks or coupons) of various diameters are cut from 5mm plate using a plasma CNC to test and find the optimal starting material size for the forging process.
0:12:24 DIY Forging Lubricant: As commercial forging lubricant is hard to buy in small quantities, a homemade version is mixed using graphite powder and molybdenum disulfide, based on Tobjorn Åhman's recipe, to help the hot steel flow into the die.
0:13:47 Test Forging & Optimization: Several test forgings are performed using different sized pucks (starting small and increasing). A 45mm diameter puck is determined to be the optimal size, providing good fill with manageable flashing and release.
0:15:25 Mass Production & Challenges: Mass production of the coins begins. However, the process is frequently interrupted as the workshop's air compressor struggles with the continuous high demand, repeatedly tripping its 63A fuse.
0:18:06 Evaluating Forging & Die Performance: The die itself withstands the forging well. The main difficulty encountered is the coins sticking in the die, attributed to the lack of a draft angle (tapered sides) in the impression, requiring prying for removal.
0:19:28 Finishing Process: Since no clipping die exists to remove the excess flashing, it is ground off manually for each coin. The coins are then lightly heated to create a uniform scale finish and finally wire-wheeled.
0:20:35 Selling the Coins: The batch of successfully forged coins, along with some unique misstamped ones, are photographed and listed for sale on the creator's Squarespace website.