Welcome to HMEM John.
One of my earliest engine build was Elmer's Horizontal Mill Engine.
I didn't have a mill in my hobby shop at that time.
You can find the plans
HERE
There is some mill work required but the parts are small and easily manipulated.
For the steam chest, I just mounted the stock in my lathe tool post and shimmed
it up and down to use an end mill in the lathe chuck.
For the cylinder port holes, I clamped the stock in the tool post, set the compound at 25° and
feed the tool post into the drill bit that was held in the lathe chuck.
It was my second attempt of building a running model engine and it looked like
a dog's breakfast when completed.
Tapped holes were breaking through the sides of the cylinder block.
Piston to cylinder fit was marginal at best.
But it DID RUN with the help of a whole lot of air pressure!
[ame]http://www.youtube.com/watch?v=Opy7Xrordk4[/ame]
I know for a fact that engine can be built without a mill.
However, seeing it work added to my desire to buy a mini-mill.
I had one two weeks later.
It doesn't have to be pretty to hook you on the model engine building
addiction. All is has to do is run once!
Rick