Adafruit V-twin Steam Engine Kit by Gakken [ADA1846]
This Twin Cylinder Steam Engine Kit has everything you need to make your own old school V-type steam engine. This kit is a great way to both learn about how steam engines work and brush up on your mechanics. It's perfect for makers, train enthusiasts, or a classroom demonstration for a lesson on James Watt. No batteries required for this kit, it uses a small flame and principles of gas expansion and contraction to create motion!
There's no English manual so this kit's a bit more challenging than the other Gakken kits. The pictures are fairly simple to follow, however, and the kit should only take a couple of hours to build. The Japanese Manual (with pictures) is here.
Gakken is a Japanese publishing company founded in 1946. In the 1970s, they began selling educational toys, books, magazines, and electronic kits. Their kits are known for their smart design and relative ease of use and have a large cult following both in Japan and the United States.