I am asked if my free plans are still available, yes they are.
Visit myfordboy.blogspot.com for details. My email is at the bottom of the page.
Lots of these engines have been made by others, see the gallery here: https://myfordboy.blogspot.com/p/more...
The tin can engine needs some soldering and a drill but the others can be made with little tools and easy to get materials.
Tin Can engine:    • Stirling Cycle Engine from Tin cans  
EZ Stirling:    • Easy to Build Stirling Cycle Engine. ...   made as a simpler version of the Tin can engine.
Pringle engine:    • Free Plans Myfordboy Pringle Stirling...   Some builders said they could not get the materials for the EZ Stirling so this one uses materials available world wide.
LTD engine:    • LTD Stirling Cycle Engine Free Plans ...   Runs on a cup of hot water or frozen peas, easy build.
3D printed engine:    • 3D Printed LTD Stirling Engine   If you have acesses to a 3D printer you might like to try this one.