PMR 7 Twin Cylinder Steam Engine

[crueby]

Looks like a gas jet manifold from science class. Hey Bill, your classroom missing one?!

[zeeprogrammer]

Well it runs. Sorta kinda.

<a href="https://www.youtube.com/watch?v=KQt8W6QFHtE" target="_blank">http://www.youtube.com/watch?v=KQt8W6QFHtE</a>

From my viewpoint... 

I don't know if I'll take this further. I'll think on it. Many improvements are needed and I think some involve getting replacement castings which I'm not willing to do.
I accomplished a number of goals. While I didn't get the model I wanted in terms of smoothness and low input power, I did learn a lot. A whole lot.
No doubt I'll keep playing with it though...tweaking this or that.

Even simple things like the crank bearings should have been slightly longer (or the connecting rods slightly thinner) so that the screw could be tightened up against the bearing.
Or improving my habits for measuring and double-checking. (And remembering to check for cutters before reaching in.  )

I could learn more on this but I think I'll do better (in terms of learning and experience) by doing some bar stock engines before trying another casting kit.

I'm pretty happy.

Many many thanks to all of you watching and helping. That's a large part of the enjoyment I get out of this.

[zeeprogrammer]

Wow! I'd turned the compressor off a bit ago but it still had some pressure.

I just went over and applied air and the engine started right up. (Which means it ran with lower pressure than the video.)

I may not be that far off.

That was cool!

I'm sure you all do the same. Get it running and then keep going back to play with it.

Okay...now I'm really 

Wow. What a feeling.

[crueby]

 

[dparker]

Zee:  I have been following your exploits for quite some time and always enjoy your posts.  This last engine looks very nice and it runs, almost on the first try, that is a great !  The problem you had in finding the binding might have been helped by taking a slow motion video of it running.  My Son and I have built several air engines and a slow motion video helped to find where the binding was very quickly on one of the air engines.  My engines can be viewed on YOU TUBE under the username "parkerdjte" if you are so inclined.  Thank You for the interesting posts and your shop is to be admired by us and enjoyed by you. 

[Kim]

Hey Zee,
you should feel pretty pumped about your engine!  Both cylinders working, and it's looking really good!  it will only get better with some running in.

Love the videos too.  Great work Zee!
Kim

[Jasonb]

Zee, best thing now would be to let it run for an hour or two with plenty of oil. It can run in the background while you get started on the next engine

[Roger B]

Looks good to me     

[Brian Rupnow]

Nice engine Zee. Knowledge is cumulative. The more engines you build, the better you will get. Some of the machining steps that appeared to be almost impossible on your first build will become routine operations. Good job!!--Brian

[Tennessee Whiskey]

Awoke this morning to the second video of the ol' #7 running. Zee, I think it's running very well. As a matter of fact, if you don't have it anchored down, it isn't showing any signs of trying to "walk around", and that's great. Now, the question everyone here loves to ask: what's next?

Cletus

[crueby]

Awoke this morning to the second video of the ol' #7 running. Zee, I think it's running very well. As a matter of fact, if you don't have it anchored down, it isn't showing any signs of trying to "walk around", and that's great. Now, the question everyone here loves to ask: what's next?

Cletus

Rhymes with zanly zeemer...

[mklotz]

Lecker.  Ich hat es ganz gern.

[zeeprogrammer]

Thanks everyone! It's very much appreciated you followed along and provided so much help. 

As for the next little project...that's a tough one.

I have the PMR boiler #1 kit but it hasn't grabbed me yet.
I think a lot about a popcorn engine (Julius's plans).
But I also think about a walking beam or marine engine.
Once in a while I think about an IC engine.

It may be a while before I start. I've got a couple of wild hairs that are bothering me and they don't involve machining.

But that popcorn engine...it includes a governor which I've not done.
And the boiler could run it.

 

[Gas_mantle]

Great stuff Carl 

I'm pleased you got it running, it's a very satisifying inner feeling when something you made comes to life 

I enjoyed your build log and hope you do another one, it's nice to see a relatively simple engine built on the forum. There must be 100's of silent members here who want to build something that is suitable for a novice and can take inspiration from something like this.

Well done 

[bent]

Try taking out the gland nut.  I had trouble getting the thread centered when I made one for the PMR #3, and it dragged on the piston rod.  If yours runs better with one or the other gland nut removed, next you need to figure out whether it's the gland nut (external) thread, or the cylinder head (internal) thread (or just leave the gland nut off, it won't leak that much without it).  I ended up remaking the gland nut which had previously been done with a die; the second go was done with single-point thread cutting.  Came out much more concentric (I also took more care boring out the piston rod hole).  Optionally, you could just bore out the hole in the nut to get it to run smoother.