Some friends of mine came up with the idea of making a commemorative coin for the 50th anniversary of Steer Roast, so I’ve taken up the project with a lot of zeal. I’m working on stamping brass coins myself. The idea is to CNC mill designs into steel, harden it, and hit it really hard with a circular brass lug in between. We may have to heat up the brass to get it to form.
This past week I worked on testing the process. I machined a test die in a CNC mill at the Edgerton Shop, reacquainting myself with MasterCam.
This is an image of the test die I made. To simplify everything I designed a die that is basically a set of extrusions, so it’s not a finely beveled 3D surface but rather more like a 2.5D surface.
I’m working with a guy in the foundry (getting a master’s degree in material science and engineering) to harden the steel and figure out the stamping process. Here’s a video of him hardening the die for me. It’s super cool.
This is the “coin” we were able to stamp with a giant sledgehammer. It has very fine detail — it picked up all the machining detail — but we weren’t able to hit it squarely so only one side picked up detail. We hope this won’t be a big problem when we have a top and bottom die, and be even less so if we heat up the brass lug.
We thought this was successful in demonstrating that it is certainly possible to do, so I’m working on making the final dies. I machined one side on Friday, and will do the other one on Monday; hopefully we can do a prototype of the final coin Monday night. Below is a video of the animation from MasterCam showing how the die will be machined.