I don't agree that Stuart are expensive - my wife bought me a set of 10V castings for Christmas, 1972 (or was it 1973?) and they were 30 pounds then, about one-week's wages. At todays price of 73 pounds, it would be 'only' 3/4 of a week's pension or a fraction of 'average' pay.
I machined that engine on an ancient Round Bed Drummond lathe using lots of ingenuity. (The only extra help I had was lapping the port-face.)
Machine tools do not need to cost thousands of pounds, dollars or sheckels. I currently use a tiny Chinese-made lathe (150 quid) and a bench drill (50 quid), to which I have added an X-Y-slides-come-vice (about 30 quid) to do sort-of milling.
The engine I'm currently working-on, a vaguely Westbury-style paddle-engine, is being machined entirely on these two machines. The castings for the engine are also home-made, in aluminium, in a charcoal (carbon-neutral) furnace in my backyard.
Geoff