Blueing relates to guns hence my putting it here. I started cold blueing tools about 3 years ago. Blueing opened a whole new world to the restoration of select tools for me, especially things like machinists parallel clamps and a host of other tools.
I have one really good tip if you blue, or intend to blue tools, guns, whatever.
Instead of simply wiping oil on a freshly blued surface totally submerge the freshly blued item in a tub of new motor oil and leave it there overnight. Doing that will result in a deeper blacker blue finish than a simple oil wipe.
Elroy has performed a few blue jobs over thhe years.
Here's an example for your viewing pleasure:
https://smith-wessonforum.com/threads/the-chief-gets-a-new-uniform.257163/
Elroy would encourage you to work additional projects.