So, fire-blueing is simple and adds a classic touch. The first step in the process is to polish the surface. Here, I have chucked the cock screw in my drill press. I use 400 grit Emory cloth to polish it until the head gleams.
I use a torch to slowly heat the screw until it turns a straw color. Then, I chase that color up the shank until the head turns a beautiful shade of blue. Once it turns that color, I drop the screw into a can of oil to freeze the color in place
