Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

According to you Jensen experts, this machine is from the days when Tom Jensen Sr. was making toy steam engines in his basement shop in the early 1930s. It has the earliest slide valve gear. It is somewhat different from the very earliest known examples in that it has an in-line throttle valve and a 'hot plate' type round heating element. In this transitional example it is likely that Jensen adapted and used older components on hand as the boiler has a fitted plug where an earlier 'chromalux' cartridge heater could have been inserted and a plug in the steam line-to-valve chest junction block where the first throttle valves were located.

Geez....that hits all the rare,unusual & not seen before early type of Jensen build. Wow.....

  Really amazing, thanks for sharing!

Thanks for your comments. I wasn't sure the dynamo needed remagnetizing (it seemed weak) but did it anyway to be on the safe side.

Wow what a great find!!!

I think this makes the 4th known D slide valve example and each one is a little different. So yes, I'd say it's "pretty rare".

Those are quite different from the one I have (had) other than the slide valve.