# A geared engine



## Oldmechthings (Dec 1, 2008)

Yesterday on a post about an air operated engine, cfellows asked where I was.
Just to let everyone know, I'm still around producing things as fast as I can, I'll post a picture for you to look at. It is a simple little geared engine, that is a little different than normal. It has a big hard to pronounce and understand name, but I do not like to use those kind of words. It uses a Bimba brand pneumatic cylinder, and that is where it got its name I gave it, and a chain driven rotary valve, just to make it different.







It has an odd number, crooked spoke flywheel, that I have taken a liking too. Remember about a year ago Powerkeg, in one of his CNC classes, programmed and routed out a pattern for it. I was given a casting and so I now use that as a pattern to make my own castings and have used it on a couple models. I call it a "Pilley" wheel after the designer.
If you would like to see a short video of the engine running, it is posted on the Blog: http://birkpetersens.blogspot.com/
       Birk ;D


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## Paolo (Dec 1, 2008)

Welcome back!!! Really intersting engine..as usual from you!!! :bow: :bow: :bow:
Cheers Paolo


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## rake60 (Dec 1, 2008)

Beautiful Birk!

I hope you don't mind my taking the opportunity of embedding that video here.

http://www.youtube.com/watch?v=4AfuRuigptk&eurl=http://birkpetersens.blogspot.com/ 

 :bow: :bow: :bow: :bow:

Rick


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## dsquire (Dec 1, 2008)

Oldmechthings :bow: :bow:

Impressive little engine that you have. Looks like a very nice runner and very nice looking.

Cheers

Don


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## Philjoe5 (Dec 1, 2008)

Very nice engine. That flywheel is too cool 8) 8)

Cheers,
Phil


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## Maryak (Dec 2, 2008)

Oldmechthings,

That just blows me away. Brilliant 
	

	
	
		
		

		
		
	


	







Best Regards
Bob


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## cfellows (Dec 2, 2008)

Nicest engine from an air cylinder I've ever seen! 

Is that internal gear actually machined into the frame? I've always wanted to machine an internal gear, but don't even know where to start!

Chuck


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## Bernd (Dec 2, 2008)

cfellows  said:
			
		

> Nicest engine from an air cylinder I've ever seen!
> 
> Is that internal gear actually machined into the frame? I've always wanted to machine an internal gear, but don't even know where to start!
> 
> Chuck



You could start out with a shaper and a tool ground to the tooth shape. 

If you've got a bit of money you can buy an internal hobbing machine or gear broaching machine. But for one or two gears it's not a good investment.

Bernd


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## Brian Rupnow (Dec 2, 2008)

Very intriguing engine. I like it.---Brian


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## Oldmechthings (Dec 2, 2008)

Machining internal gears for models is quite simple. On this model the gear teeth are machined right into frame. After boring out the inside, the blank was mounted on a rotary table on the mill, the mill spindle rotation locked, a form tool inserted in a boring bar, and the quill worked up and down by hand like a vertical shaper. After each stroke the table is advanced a couple thousandths, until the proper depth was reached. Index to the next tooth and start over. It really goes quite fast once you get coordinated.
  Certainly everyone has experienced cutting keyways in the lathe by running the carriage back and forth. This about the same thing. In fact, If you wanted to rig up an indexing mechanism for the lathe spindle, there is no reason why it could not be used to machine an internal gear.
  Expel those negative notions in your head that you cannot do that kind of an operation in your shop, and just go ahead and do it. Surprise yourself and all your friends in the process! Stick a big feather in your hat and parade around town. When asked about the feather tell them YOU DID IT!
           Birk ;D


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## kustomkb (Dec 2, 2008)

Very nice!! ;D

its great to be able to seethe planetary action.

I have a couple gears and air cylinders and might try and have a go one day.
Could you tell us a little more about the valve arrangement, are the sprockets 1:1?

Thanks,

Kevin.


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## cfellows (Dec 2, 2008)

Birk, how do you derive the shape of the form tool?

Chuck


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