# Thinking small



## GailInNM (Jul 31, 2008)

I built this pair of engines about a dozen years ago. I thought some ou you might enjoy seeing them. 

The "large" one is 1/8 inch bore and stroke. 

The smaller one is 1/16 inch bore and stroke. It is a half scale version of the large one. The cylinder tension spring is made of 0.004 hard drawn brass EDM wire. I lost about half a dozen of them before I finally got one installed. Flywheel is 1/4 inch diameter. It sounds like a very small bee when running as it runs at about 40,000 RPM at 15 PSI according to my optical tachometer. It is a little bit of a bear to start. It's hard to get it up to a starting speed by hand as the low end speed that it will run at is about 15,000 rpm. A small DC electric motor with an O-ring on the shaft to press against the flywheel works well however. 
	

	
	
		
		

		
			





Gail in NM,USA


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## Divided He ad (Jul 31, 2008)

Sweet! that's what I call tiny!  8) 

I know I'm not going to be alone when I say.... Have you got a video? ;D 

You must know what we're like by now Gail... We all love moving pictures  

I don't think I'll ever even attempt such a miniature endeavour... I'd probably crush most of it!! It'd be hard enough for me to make the bigger one!! : 



Ralph.


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## kvom (Jul 31, 2008)

Do that make microscope toolpost mounts ??? That's what I'd need to think about making something like that. Very cool.

Reminds me of a time when I was at university in the late 60's. Someone had built what, at that time, was the world's smallest electric motor. You needed a microscope to see it. http://www.guardian.co.uk/science/2004/jun/10/science.nanotechnology


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## sparky961 (Jul 31, 2008)

Those are quite impressive.

Are the plans/drawings available (perhaps on very small paper)?

-Sparky


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## Metal Mickey (Jul 31, 2008)

Its good to know the good old BBC could squash the small electric motor......


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## GailInNM (Jul 31, 2008)

Ralph,
No video. At the speed these run at all that happens is the cylinder looks blurry and there is nothing else moving that will show up.

Sparky,
I just checked and the drawings for the 1/8 bore engine survived the great computer crash of '02. They are not dimensioned, but I can do that in a short time if any one wants to build one. I just picked up the dimensions as I needed them from my CAD sketch. There were never any plans drawn for the 1/16 inch bore. I just built it half scale from my 1/8 bore drawings. They really are not that difficult except for drilling a couple of small holes.

Gail in NM,USA


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## sparky961 (Jul 31, 2008)

Seems to me this wouldn't be a good first engine to attempt. That said, It's one of those things with a lot of "neato" factor to it, to I'd love to add some dimensioned plans to my archive here for when I get a round tuit.

-Sparky


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## CrewCab (Jul 31, 2008)

GailInNM  said:
			
		

> It is a little bit of a bear to start. It's hard to get it up to a starting speed by hand as the low end speed that it will run at is about 15,000 rpm. A small DC electric motor with an O-ring on the shaft to press against the flywheel works well however.



Did Ducati base their GP bikes on your design Gail  ......


......... I can't even imagine trying to build a working engine of that size, never mind the eyesight considerations............ how do you inject compressed air into a "bumble bee" ............... OK don't answer that one guys :

Brilliant work Gail, and thanks for sharing your insight and experience ........... just think of me as a "sponge" ................ trying to soak it all up.

CC


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## Tin Falcon (Jul 31, 2008)

cool engines gail 
would not mind a set of dimensioned sketches when you get a round to it. Like i really need to start another engine project !!!
Tin


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## Jere (Jul 31, 2008)

These seem more my size! I am a watchmaker, and I occasionally lurk around this site to read the interesting posts, but usually don't know much about the subject matter, but anything related to metalwork draws my attention.
I use a watchmakers lathe and parts on the micro scale are the norm.

I too look forward to seeing the plans for your engine, thanks for sharing.
Jere


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## Divided He ad (Aug 1, 2008)

Another hands up over here Gail.... If I can't see it on video I'll just make one and see it first hand ;D 

When your ready... I've got a backlog of work that's scaring me right now!!!





Ralph.


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## slink74659 (Aug 6, 2008)

That's a small one.
I'm all for seeing the plans also.


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## GailInNM (Nov 17, 2008)

Sorry about the plans everyone. My computer files of the plans are somewhat screwed up and I will have to redo some of them. I need to get some other things done first.

In the meantime, Steve Huck has recreated both of these engines and has video of both of them on UTube.
http://www.youtube.com/user/stevehuckss396

While you are there check out his co2/air powered V8. I think the plans for it should be in the next issue (issue 17) of Model Engine Builder.
Gail in NM,USA


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## kustomkb (Nov 17, 2008)

That V-8 is slick, could the block be made out of polycarbonate or plexi? 

As for the first video it sounded cool but all I could see was...errr..pardon?


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## RFThomsen (Nov 18, 2008)

Hi

I Hope this is not considered a hijack? 

No drawings! It's my third engine. It has a bore of 3mm. (very close to 1/8) and a stroke of 8mm. (That's roughly 0,31496062992125984251968503937008 inch) :big: oh yes: This is a STEAM engine! 










It's very hard to heat up all that brass, so it's a god idea to preheat the hole rig!


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## SignalFailure (Nov 18, 2008)

Nice one Rene!

PS Is there a safety valve??


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## RFThomsen (Nov 18, 2008)

Ah safety valve!!! Yes of course.
 When the pressure gets too high, the hole thing will explode, and unleash the pressure. 

Serious! I use commen sense.


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## Mcgyver (Nov 18, 2008)

An oscillating engine like that sort has a built in pressure valve, the spring holding the piston in place. That spring has to be fairly light or the engine won't run. So unless one starts adding valves or throttles i think it would be quite safe


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## SignalFailure (Nov 18, 2008)

Yup, I've made a few of those and keeping the steam in is the usual problem 

However, my fear is that an errant bit of solder or build up of scale could block the pipe from the boiler (maybe if it's constricted where it bends or enters the steam block) which could result in a rapid change of trousers.


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## RFThomsen (Nov 19, 2008)

If you don't have steam streaming out, some think is wrong, and it would be a good idea, to blow out the flame!

I meant Gail, and not Paul :-[ Sorry
Hey Gail, Was it hard to get the 1/16 running? I was convinced that 1/8 would be the smallest, you could get running.

Do you have a 1/16 reamer?

Have you heard of Iqbal Ahmed?

http://www.craftsmanshipmuseum.com/images/Iqbal22.JPG

http://www.craftsmanshipmuseum.com/Ahmed.htm

(I hope that you will bear whit my grammar? English is not my native language)

René


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## stevehuckss396 (Nov 21, 2008)

I made my half and quarter scale just a bit more true to the original project.


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## stevehuckss396 (Nov 22, 2008)

I have posted the plans for the 1/2 and 1/4 sized engines. They are in the plans section under "Mini and Micro HOSC". 

The micro was hard to film without getting blurry. The air fitting is almost the same size as the entire engine
[ame]http://www.youtube.com/watch?v=DMqJ6heXO6U[/ame]

The mini is almost exact to scale.
[ame]http://www.youtube.com/watch?v=pRZglkDeSuQ[/ame]

The original project. One with the old style casted cylinder and one with the CNC made cylinder. The older one runs on 2Lb of air. 
[ame]http://www.youtube.com/watch?v=1-BJkG-t9tw[/ame]


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## GailInNM (Nov 22, 2008)

Steve,
I copied the plans into the Downloads and uploads section of the site so they would be easier to find when this thread gets buried with time. Thanks for posting them.

I still don't understand why your engines look so much nicer than mine.  ;D ;D
You do very nice work. :bow:

Gail in NM,USA


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## stevehuckss396 (Nov 22, 2008)

GailInNM  said:
			
		

> I still don't understand why your engines look so much nicer than mine.
> 
> Gail in NM,USA



I have a better camera! Hahaha!!


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