# Simple Oscillating Air Motor



## SAM in LA (Mar 15, 2010)

LMS Oscillating Engine kit which included all of the materials, drawings and DVD instructions. http://www.littlemachineshop.com/products/product_view.php?ProductID=3485&category=
 I didnt think to take pictures when I first started on this air motor though I will do a better job on the next build. I would not have been able to do this if it were not for all of the members builds that I read, and saw, on the forum. Thank you.

I started with the flywheel and faced one side then flipped it over to face the other side. I drilled and tapped for the shaft, and cut the recess. I threaded a stub shaft to mount the fly wheel too, so I could recess the other side. This photo shows the flywheel mounted on the stub shaft and being polished.













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I turned the crankshaft eccentric and drilled and tapped for the set screw.






I had to let this part overhang so the drill chuck would have enough clearance.
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I then set this part up so I could D & T for the crank arm. 




Time to square up the block for the cylinder.





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Squared up the vertical plate.






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Drill, counter bore through the bottom of the base plate. The vertical plate will be fastened with the socket head screws through these holes.





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The next setup shows how I had to mount the vertical plate so I could drill and tap for the screws that come up from the base plate. The AL plate is clamped between 1-2-3 blocks. It took me a while to figure out how to do this with what I had. The next time should be easier.





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Next, I drilled the inlet/exhaust port and D & T for the cylinder pivot. I had to raise the vice so the drill would reach it.





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I had the use my four-jaw chuck to offset for the cylinder. This was not as hard to do as I feared. You just have to get it straight in your head which way the indicator is telling you to move the piece.






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Drill ½ inch for the cylinder. I do not have any reamers at this time, so I used nice sharp bits to drill the hole. I stepped up in size from ¼ inch to ½ inch to make the hole as straight as possible.





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I then turned the piston and rod. I made the piston with 0.002 clearance to the cylinder. The picture below shows how I held the piston to drill the hole for the pin that connects the rod to the eccentric. I should have used a piece of AL rather than a hard nut as a spacer to hold the rod down.





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Here it is assembled, warts and all. 







To get it running, I used lots of light oil and about 20 psig air. Once it started, I let it run for about 20 minutes. The set screw that locks the crank eccentric to the shaft would not tighten and was causing problems with it running. I dimpled the shaft and that helped a lot.
I posted a video on YouTube, once it was running; I cranked the air pressure up to 110 psig.
[ame]http://www.youtube.com/watch?v=wBRRpVssJyA[/ame]
The motor loosened up quite a bit after this run. So I decided to put an AL/Bronze bushing in the upright and make a new shaft to tighten up the clearances. I also cut out some of the uneeded material on the sides of this piece. You will see it a few photos down.





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I threaded the new shaft using the pivoting threading tool I built last month.





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Here is the finished shaft along with my C-o-C.





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Here are the pieces all polished up.





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Here is a shot assembled.





















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After looking at it for a while, I thought that it needed a little color, rather than just polished AL. I had some purple spray paint, so that made the choice easy.



Here it is running with its final set of clothes.

http://www.youtube.com/v/1Ly4GfjSID0&hl=en_US&fs

This has been fun. I learned a lot and how to adapt. Thanks to all of you that posted your builds. If I had not read them, I doubt I would be where I am now.
SAM
3/15/2010


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## black85vette (Mar 15, 2010)

Nice looking and runs well too! Thm: Those are fun projects. Thanks for sharing yours.


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## kd7fhg (Mar 15, 2010)

Nice looking engine. So whats next?

Rex


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## Metal Butcher (Mar 15, 2010)

Good job Sam! Your engine turned out great! :bow:

I like the polished finish, along with that nice blue color. It's a eye catching combination that sets your project off.

That's an interesting air line connection you used. I have not seen this type of set up before. Could you give us a little information about it?

-MB


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## Foozer (Mar 15, 2010)

Da Purple Air Eater


Looks Good all polished up


Robert


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## Maryak (Mar 16, 2010)

Sam,

Excellent wobbler. :bow: :bow: Love the colours.

Best Regards
Bob


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## SAM in LA (Mar 16, 2010)

Metal Butcher  said:
			
		

> Good job Sam! Your engine turned out great! :bow:
> 
> I like the polished finish, along with that nice blue color. It's a eye catching combination that sets your project off.
> 
> ...



Thanks.

The air connector was included in the Little Machine Shop kit. It is a quick connect type fitting. It is a 10-32 thread.


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## SAM in LA (Mar 16, 2010)

Foozer  said:
			
		

> Da Purple Air Eater
> 
> 
> Looks Good all polished up
> ...



Thanks Robert.

Da Purple Air Eater :big:

I like that name, I think I'll use it.

It doesn't take long to eat its way through a 25 Gallon air tank.

SAM


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## SAM in LA (Mar 17, 2010)

SAM in LA  said:
			
		

> Thanks.
> 
> The air connector was included in the Little Machine Shop kit. It is a quick connect type fitting. It is a 10-32 thread.



MB,
I did a little looking around this morning. The air fittings are called "One Touch Air Fittings" Mcmaster.com has them, a couple of bucks each.

SAM


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## Metal Butcher (Mar 17, 2010)

SAM in LA  said:
			
		

> MB,
> I did a little looking around this morning. The air fittings are called "One Touch Air Fittings" Mcmaster.com has them, a couple of bucks each.
> 
> SAM



Thanks Sam. The connection caught my interest and I had to ask.

-MB


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## BigBore (Mar 17, 2010)

Great build. Thanks! This will be a good one for those of us who need to improve our skills before taking on the "big" builds. I have, with Sam's permission, uploaded the PDF of this build to the _Downloads and Uploads _area.

Ed


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## SAM in LA (Mar 17, 2010)

Metal Butcher  said:
			
		

> Thanks Sam. The connection caught my interest and I had to ask.
> 
> -MB


MB,

When I am ready to run my second build, I'll order some of the "One Touch Air Fittings". If I buy them now, I'll either lose them or forget that I have them.

SAM


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## hobby (Mar 17, 2010)

Sam,
That's a beutiful engine,
I like your ingenious setups, that's what make this hobby extra interesting,
As I was going thru this thread the farthur down I got the better and better your engine became, 

I wanted to especially say, tremendous job on the polishing you did on it, those reflections looked good on it.

Then as the thread continued it got better with the pain job on it, then when you ran it the second video. wow, professionaly done, that is a very nice smooth runner.

Good job all around...


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## SAM in LA (Mar 17, 2010)

kd7fhg  said:
			
		

> Nice looking engine. So whats next?
> 
> Rex



Rex, 

Thanks,

I may build some sort of Beam Engine. There are a couple of tooling type jobs to do and I need to replace the bearings in the lathe/mill to tighten things up.


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## kd7fhg (Mar 17, 2010)

Sam, another nice job and I for one am looking forward to your next build.

Rex


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