# My Rocker - first runner



## rleete (Jul 19, 2009)

Inspired by the thread Stew posted, I decided to try making one of Elmer's rocking piston engines. As usual, I just couldn't leave good enough alone, and made some of my own changes. The most obvious one was to bore the cylinder through, and add an end cap like Mklotz of HMEM did. The cap is actually 2 pieces, with the tube threaded into the end of the cap. The second was because I didn't have any flat head screws, so I bored out the crank and used a button head. The base is not attached by a screw, but press fit and cold riveted over. I also soldered the bushing into the side, after running it and finding it flopping all over.

My first running engine, which happily ticks over on less than 1 P.S.I. I can actually keep it going on lung power alone, but that will make you dizzy in short order. At 20-25 P.S.I. it screams along like a weed wacker.






















I only had to remake 2 parts, which is astounding in itself. The first was the shaft, because I tried to use drill rod, and snapped the tap off in the end. Remade in brass. The other was the inlet tube, which I single point threaded 6-32. When I drilled the through hole, it broke through the minor diameter of the threads. So, I refaced it, and cut the threads to 8-32 instead.

Runs pretty nice (sounds exactly like Stew's in his video), and was a big hit this afternoon with the neighborhood kids. They especially liked it when I ran it wide open on 25 P.S.I. I'm pretty impressed that I got the whole thing done so quickly, and that it ran right away.


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## vlmarshall (Jul 19, 2009)

Nice work! You guys are slowly drawing me in... darn Projectitus. :big:


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## Foozer (Jul 19, 2009)

If mine comes out as nice as yours, I'd be tickled pink.. looking good, love those tiny parts do you?

Robert


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## arnoldb (Jul 20, 2009)

Well done rleete - great feeling when it just starts up & run!
Regards, Arnold


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## SBWHART (Jul 21, 2009)

Nice job I like the contrasting materials you've used,

Have fun

Stew


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## Tin Falcon (Jul 21, 2009)

Good job still need to get my two done.
Tin


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## rleete (Jul 21, 2009)

Foozer  said:
			
		

> love those tiny parts do you?



Strained my eyesight on this one a little. I can't imagine working on smaller stuff without having a magnifying glass.


Thanks for the nice comments. I know it's not quite up to PotM standards, but it's my first so it will always hold a place of honor.


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## dreeves (Aug 14, 2009)

Where can i get plans for this engine. I have seen many built and run but no plans. Looks like a fun engine to build


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## zeeprogrammer (Aug 14, 2009)

I think this is the thread that infected everyone.
SBWHART.
Drawings are in Stew's first post.

http://www.homemodelenginemachinist.com/index.php?topic=5461.0

Apparently the only cure is to build one.
Please show pics.

Hope this helps.


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## tonphil1960 (Sep 7, 2009)

First runner huh? Nice work, tell me how frustrating was it really. I am new to machining too. Getting my lathe in a week or so. This might be a nice engine to start with for me. Did you use a lathe and Milling machine ? Unfortunately I will be getting only the lathe for now, but also the milling attachment so I hope I am good to go. That little thing must really crank at 25psi ! !

Regards Tony


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## rleete (Sep 9, 2009)

Well, it's actually fairly simple, but some of the dimensions are not as clear as I would have made them, so a little figuring is in order.

It runs well (ran the first time I put air to it) and can spin like mad on 20 PSI, or chug along on less than 2. Having demonstrated it many times over the past few weeks, it runs even better, and I can keep it going on lung power for 30 seconds or so. It actually seems to like a bit of a loose fit. Ironic, since I spent extra time meticulously fitting the piston to the bore.

There are quite a few examples of this one on this site, as it seemed to be the engine of the moment a few weeks back. As you will see with a bit of looking, there aren't too many critical dimensions. Lots of opportunity to personalize it, but since I usually spend so much extra time doing that, I elected instead to finish it to plan. The worst part of the whole thing is that the parts, being tiny, tend to get lost in the swarf and clutter if you aren't careful.

I did use both a lathe and a mill, but most of the mill work could be eliminated. A file (it _is_ just brass) and sandpaper to take care of any flats necessary, and rounded surfaces for the rest. I did mine in one concentrated weekend; a total of about 16 hours work, start to finish.


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## ozzie46 (Sep 9, 2009)

Well done rleete. Nice looking rocker. Must resist,to smaall for my arthretic fingers. :big: :big:

 Ron


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## Maryak (Sep 9, 2009)

rleete,

Good one. :bow: :bow:

Best Regards
Bob


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## JimN (Sep 10, 2009)

Nice looking engine. Congrats on it runing so well.


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