Elmer’s Wobbler
In choosing your first build project you can do no better than starting with Elmer’s Wobbler. No complicated valves to construct and no timing to set.
- A simple design
- Runs very well
- Can be made in just a few days
- The plans and build notes are free
The satisfaction of completing your first engine that springs into life when you run some compressed air through it will leave you with an ear to ear grin for days. It gives you the encouragement to progress to more complex and demanding designs but as a first step into model engineering Elmer’s Wobbler is unbeatable. It should only take a few days to build but the satisfaction of producing a runner will have you hooked on this absorbing pastime.
William, my 11 year old grandson makes Elmers Wobbler with just a little help from me. Clearly an engineer in the making !
You can download the plans and build notes (totally free of charge) for Elmers Wobbler #25 from
http://www.john-tom.com/html/ElmersEngines.html
Whilst you are there you can of cource take a look at other designs from this prolific engine designer but for now proceed with this simple wobbler design.
step by step photographs
Being a professional photographer when Timothy Evans built his wobbler he took a series of over 60 superb photographs showing the machining and construction of his engine step by step.
Whilst Timothy used his milling machine to make the frame for his engine you can get by using hacksaw, files, etc.
Similarly whilst Tim used collets to hold stock in his lathe you will be perfectly OK simply using your three jaw chuck.
Tim took these measures to enhance the accuracy of his machining but it is reassuring to know that these little engines are very tolerant to slight machining inaccuracies although you should always strive for the highest level of accuracy you can achieve. The higher the level of accuracy you can achieve the better your engine will run and, importantly, on less air pressure.
When marking out the frame I suggest you spray one side of the aluminium plate with a coat of primer/undercoat. You will be using WD40 as a lubricant for cutting, drilling and machining and WD40 will wash your scribed lines away if you have used a broad blue felt marker – a popular marking out medium.
Photograph of completed Wobbler with the simple but all important drilling jig which ensures accurate positioning of port openings
Success is aided with the use of a simple 3 hole drilling jig which ensures that the ports for air or steam align perfectly between the back of the cylinder and the frame.
Steam or air ?
In my ignorance I originally thought all steam engines ran on steam. Well they do of course but the good news is they run equally well on compressed air and believe me that’s the way to go. Building boilers is not as easy as it may appear and the potential danger from a poorly constructed boiler should not be under estimated.
You will find step by step notes with photographs in the projects section.
John,
Not only are your machining skills excellent but so are your photography skills. I think you should write an article telling us how you photograph your engines so the rest of us can learn how to take better pictures to post on forums or our web sites.
I love the effect given by reflective surfaces you often photograph your engines on.
Thanks Rob
Whilst your kind comments are very much appreciated I am very critical of my machining capabilities. Like all of us I strive to improve but compared with the standard I see within others I have still a long way to go. Still, the pleasure and satisfaction is in the journey and it’s the making of progress that bring the most satisfying of rewards.
As for my photographic ‘skills’ I don’t regard myself as other than average. One thing that I do feel is a great help is the use of a tripod particularly in workshop conditions where long exposures are often called for. The use of the tripod avoids camera shake and the result is sharper images.
John
Brilliant stuff.
Thank you.