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

Of course I know that the coin does not provide a definite date for the engine, but I think we can safely assume that the builder used a coin readily at hand, and not likely a very old one. So if it was built in say, 1870, that's 154 years old which is why I used 150 years or up to 1874. And absolutely not a later repair--the eccentric rod came unsoldered from the disc while I was testing it and the whole eccentric disc fell apart when I tried to solder the rod back on. I had assumed it was one machined part but the coin was an inner, smaller diameter disc soldered between and keyed to two larger diameter discs, The eccentric strap has an inner ridge which fits into the "groove" created by the smaller diameter coin, thus centering and holding the strap while allowing the disc to rotate freely, a clever design.