This is a little different than what most of you are posting.
I just finished this after about a year of spare time machining. It is made from scrap steel and brass that I acquired.
It's somewhat of a copy of engines used on European side wheelers in the 1850's
I run it on air, but there is no reason that it wouldn't run on steam - other than I don't have a boiler setup.
It runs on about 10psi of air pressure.
Thanks for watching.
Scott