I would like to suggest a new user group. Model engineering. This includes people who like to build model steam engines, locomotives. There are web sites that cater to amateur machinists and live steam. The U.K. hosts many amateur machinist sites. I think a place on this forum would be nice as hobby topics involve engineering.

I utilize most of the engineering disciplines when building large scale locomotives and machine tool projects. It's more than a hobby with me. I learn and innovate along the way.