Green Twin Oscillator

A Canadian modeling buddy of mine showed me a couple of photos of a twin oscillating steam engine back in 2011, and I helped him with the 3D modeling work.

We initially were going to make the engine from bar stock, but I decided that this engine really needed to be cast, so we 3D printed some of the patterns, including the flywheel pattern, and hand-made other patterns from wood and steel.

After setting up a home foundry, and lots of trial and error, we were able to make to flywheels in gray iron, and the remaining parts in 356 aluminum.

Most of the machining was completed during the holidays at the end of 2015, and my Canadian buddy was able to complete his engine and run it.

I have been busy with work projects, and so I have only been able to complete and run one cylinder. I used temporary commercial fasteners to check the alignment and fit of the parts, but I am making custom "old-style" bolts and nuts for all the fasteners.

The pistons and rings are gray iron. Connecting rods are steel. Bearings are bronze.

It has been a very enjoyable build, albeit with a long and difficult learning curve.

This is a video of my Canadian buddy's engine running for the first time.

This engine is a 60% scale of the full size engine, and has a 6" diameter flywheel, and a 1.25" bore.

Edited By Neil Wyatt on 16/02/2016 09:22:09

Here is a comparison of the 3D model we created, compared with a photo of the original engine that was listed for sale at Preston's Services.

Edited By JasonB on 17/02/2016 10:18:29

Here is the model engine I am constructing, with one cylinder fitted.

Edited By JasonB on 17/02/2016 10:19:16

And here is the full size Preston's engine running, so you can hear it with sound.

I will add a video of my engine running when I get the second cylinder completed.

Edited By Neil Wyatt on 16/02/2016 09:21:21

hello Pat,

Either that's a very small engine or the photos are just thumbnails.

Can you upload larger pictures?

Neil

These are the same images I have used elsewhere, and the size seemed to be fine, but for some reason the pictures seem to be getting reduced to thumbnail size here, I don't know why.

its not something I am doing.

I've made it grow a bit

Never seen that happen before. Oversize images are reduced to 1024 pixels in the longest dimension, but I've never seen them reduced to that size before.

Nice engines, by the way.

Neil

The images are actually on modelenginemaker so in my case as I'm not logged in on this browser I just get an empty box.

John

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LOL Now I am logged in I get fixed sized images that just fit in the normal thread width.

John

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The images may be the same as elsewhere, but the ones in the thread here are linked to an album, and they are very tiny in the album.

Neil

**LINK**

That's the link to the first image going back from here Neil. I know the others are the same because they wouldn't show until I logged into modelenginemaker.

John

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I used Images from MEM to get the larger ones, there is still a problem with the small ones in Pat's album

Ah, I hadn't realised Jason had linked to MEM - but as most people here won't be logged in to that website they will be as confused as I was.

Neil

Sorted now with images hosted here in Pats album

I reloaded one of the images.

It is about 125k, so it should be about the right size.

I originally intended to cast the entire model in gray iron, but due to the difficulties of melting and pouring iron, I was only able to cast the flywheels in iron.

If I can get my iron technique to be more reliable and consistent, I may revisit this engine and cast the cylinders and base in iron.

That is the beauty of having patterns, if you don't like what you get, you can cast another one.

P.S. - Thanks for the help Jason.  These current photos seem to be working.

I don't have an MEM membership, and can't see any photos on that site, so I am not sure what my buddy posted over there.

Edited By Pat Jorgensen on 20/02/2016 19:24:59

Edited By Pat Jorgensen on 20/02/2016 19:26:02

Let me congratulate you on making this fine engine.

Everyone else seems more interested in the size of the photos.

There is a lot of work in making patterns and casting, not many people can make such a nice flywheel from iron. well done it runs a treat.

Thanks Engine Builder, I appreciate it.

My dad built a number of model engines, but unfortunately I was never able to connect with him long enough to find out how he did it all.

I have to credit JasonB for inspiring this build; both indirectly through his fabulous engine work, and directly through very helpful feedback that has gone on for years.

My only other engine work has been two copies of a simple wobbler, made from bar stock, so this engine was a quantum leap for me. My intent was to make it exactly like the original engine, and I think I have generally succeeded in doing that except for the original engine being all cast iron construction.

I had to build a foundry, and learn how to cast metal, and so that took some time.

And I had to learn 3D modeling; it took about a year to get a firm grip on that.

And I really had to advance my machining skills; this was my first attempt at machining castings.

This engine started on a whim, but I am quite pleased with the results, and I think my Canadian buddy is quite pleased too.