Potty Popcorn Engine

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sbwhart:
This will be a long drawn out project as I plan to fit it in around work on my loco, there will be a good few weeks between each part so any one who wants to follow along and build an engine with me is more than welcome.

John showed me a drawing he had of a popcorn engine some time ago, and a few weeks ago I cam across a picture of a popcorn engine on the web, this got me doing a little research into them.

This is the type of popcorn engine I'm planning on modeling its a Dunbar Popcorn Engine, the model is going to be 1/3 scale so it can be made on small machinery, and i just had in my stash a lump of brass that would make a 1/3 scale flywheel.

All the engine pictures I've found are different the only thing that they all have in common is curved flywheel spokes.

So the flywheel is the first part I've made, the spokes don't have to be curved, but I liked the challenge of making a flywheel with curved spokes.

This is the only part drawn up so far, the remainder I'll get drawn up over the next couple of weeks and as i do each part I'll post the drawing for those who want to follow along.

So her we go.

This is the chunk of brass to make the flywheel a scrap yard find

First job gripping on the out side skim up the face and the OD to give two clean surfaces to work on.

Then gripping on the inside turn up the OD to size and skim the other face.

Then using some shim from a drinks can so you don't damage the OD finish off the bore and skim to width.

That the rim done

Next turn the hub down drill put a 5mm roughing drill down the middle.

Don't part the hub off you'll do that last when the spokes are fixed.

Transfer over to the mill and cross drill and tap 1/4 ME

To bend the spokes you need to make a bending jig.

The spokes are made from annealed 1/4 brass bar its important the brass is annealed, just heat it up to red heat for a minute or so and either quench or allow to cool.

The bend is done it two stages

Stage one

Stage two reverse bend around pegs.

Spokes done

Cut spokes off to length and thread a short length 1/4 ME and screw into hub with thread lock allow to cure.

Over onto the lathe with a sharp tool gently skim the spokes off to a nice tight fit in the rim.

Fix to rim with high strength loctite.

I'll let the loctite cure for a few days before I finish the flywheel off.

Stew

PTsideshow:
Looks like you have a good start on it. Here are some photo's of a Dunbar popcorn wagon and one of the engines. It is Paul Newman's original wagon he used when he started the popcorn brand. A complete Dunbar are much more rare. this museum is a museum about popcorn since it is in the popcorn belt

Paul Newman's Dunbar

The Dunbar in place

Cretors engine

Another Cretor's engine

a Cretors horse wagon

a Cretors truck

A Cretors wagon

I have the casting kit for a ½ scale Cretors from Meyers Engine Works

Dunbar worked for Cretors and then left to start his own firm, One thing about both Dunbar and Cretors engines they didn't make the engines in house after a while they framed them out that is why there are so many slight variations in the engines as long as the bases. and the holes and piping lined up they where good to go.

In the Sept/Oct issue of Live Steam & Outdoor Railroading volume 45 their is an article on the Cretors engines by my friend Art Gaier.

One more minor item, they are not popcorn engines, they are peanut roaster drum turning engines. after they figured out a way to pop the popcorn as they improved the cooking equipment, they made drive gears, sprockets and chains to drive the popcorn popper stirring rod, so it wouldn't burn.

assorted engines

Model 2 wagon

Some of the advertising cuts form one of their catalogs

PTsideshow:
And as an added bit of information. Under the books section I can recommend all of the books and booklet (reprints) of the catalog. Great stuff! :thumbup:

spuddevans:
That looks like a nice project Stew, and I love the curved-spoke flywheel, something I want to try in a future build, so I'm taking note of how you assemble it :thumbup:

Tim

arnoldb:
Good start Stew :thumbup: :thumbup:

Chair and popcorn pulled up for the build!

:beer:, Arnold

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