# Potty Elbow Engine



## SBWHART (Feb 24, 2010)

Hi Chaps

Quite a few months ago I stated a build of two Elbow Engines, I completed and got No 1 running and put No 2 on the back burner, two weeks ago I decided to complete No 2:- Hers a few pics of the build.

Valve port







Drilling the base






Milling out the flywheel hub






Turning the flywheel rim






Boring the hub






Composite fly wheel assembled with high strength loctite






Putting a bit of fancywork on the cylinders






Adding radius to upright






Squaring up an elbow






Assembled engine after first test run






I've got to tidy up the base and give it a good polish then I'll post a video of it running.

Cheers

Stew


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## BigBore (Feb 24, 2010)

Very neat engine. I just watched it on YouTube and looked at the plans on John-Tom.com. Mesmerizing motion. I'll be looking forward to your video and any other photos that you find. Thanks, this one is new to me. (not hard to do)

Someday........

Ed


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## Deanofid (Feb 24, 2010)

Nice one, Stew. You make a good lookin' flywheel there, mister.

Dean


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## bearcar1 (Feb 24, 2010)

I rather fancy the scallops around the perimeter of the cylinders between the bores, it gives a very utilitarian effect to the pieces. Great looking flywheel too. Well done. :bow:

BC1
Jim


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## wes (Feb 24, 2010)

Looks great! Can you post a direct link to the plans?

Thanks,
Wes


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## SBWHART (Feb 24, 2010)

Thanks for you kind comments and support chaps

Her you go Wes

http://www.john-tom.com/MyPlans/Steam Engines/ElbowEngine.pdf

The plans make it look a deceptively simple engine but in reality its very difficult engine to get running, as many on her will testify, squareness and alignment of the components are a critical feature of the design, you need set ups and machining methods that ensure you get squareness and alignment spot on.

I deviated from the plans quite a bit:- incorporating ideas from John Bogstandard along with some of my own, to try and avoid some of the pitfalls, I'm in the process of drawing my version up and will post them on her.

Thanks again

Stew


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## rake60 (Feb 24, 2010)

Beautiful build of the Elbow Engine Stew! :bow:

I have a love/hate feeling for that engine.
I love the simplicity of it's design, and hate it for busting my.....
well, for frustration it caused me in getting my first attempt at to run.

Rick


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## Blogwitch (Feb 24, 2010)

Nice one Stew, you learned a lot from that first one.

A good name for it - 'The Revolver'


Blogs


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## Stan (Feb 25, 2010)

I will confirm that it is not an easy project. Multiple parts of elbow engines lie on the back of my bench waiting for a day when I feel so good that I just have to beat up myself again.


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## arnoldb (Feb 25, 2010)

VERY nice elbow engine Stew :bow:

Looking forward to the video!

Regards, Arnold


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## kendo (Feb 25, 2010)

Hi Stew 
       Great bit of work you've done there can't wait to see the video

                        Ken


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## SBWHART (Feb 25, 2010)

Thanks again for you comments guys.

Test run the engine in comparison with No 1 engine this one runs a lot better, it keeps running for twice as long with a full tank of air. I'm going to have to have a good look at No 1 and try and get the same performance from it.

Finished the bling work, I don't like thing over done with shine, its a personal thing but to much polishing makes them look like they've had melted chocolate poor over them, not as there is anything wrong with melted chocolate, but not over an engine, I like them to look crisp and honest looking.

Any way hers a pic of No 1 and No 2






And a one for the album






And her,s the video.

[ame]http://www.youtube.com/watch?v=zVjsiqzU6Cs[/ame]

I'll crack on and get the drawings completed which will be next week some time.

Have fun

Stew


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## arnoldb (Feb 25, 2010)

I love it ;D - thanks for the video Stew!

Now, would that magic dust perchance be some form of graphite powder ?

Kind Regards, Arnold


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## kustomkb (Feb 25, 2010)

Awesome job stewart!

Like John said the cylinders look like revolver chambers which I think looks cool.

Thanks in advance for the drawings.

edit: I didn't catch the cartridges the first time. Obviously intentional, nice!


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## mklotz (Feb 25, 2010)

Very nicely done, Stew. The revolver cylinder look-alike, complete with fake cartridges, is a stroke of pure artistic genius.

Given the meaning of the term in American English, I should point out to the folks on this side of the pond that, to the British, 'potty' means loopy or nutty.


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## kendo (Feb 25, 2010)

Hi Stew
      Just seen the video, absolutely brilliant, and not a wobble in sight.
      At one point a thought it was going to take off ,it was going that
      fast.
      Extremely well done, love the bling by the way ( revolver chambers )

                 Ken


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## SBWHART (Feb 25, 2010)

arnoldb  said:
			
		

> I love it ;D - thanks for the video Stew!
> 
> Now, would that magic dust perchance be some form of graphite powder ?
> 
> Kind Regards, Arnold



Arnold

No the magic powder was just John's skill and knowledge in getting the best out of these little engines we make.

Thanks Marv 

Potty is also a nick name we use for Stewart:- stew pot = potty, dare I ask what potty means in American English

I'm pleased you Guys have enjoyed the video and thanks again for your comments

Stew


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## Maryak (Feb 25, 2010)

Stew,

Brilliant. :bow: :bow:

Best Regards
Bob


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## Deanofid (Feb 25, 2010)

It runs just fabulous, Stew! One of the best Elbows I've seen yet.



			
				SBWHART  said:
			
		

> Potty is also a nick name we use for Stewart:- stew pot = potty, dare I ask what potty means in American English
> 
> Stew



Well... Maybe this will give you an idea. I do some potty engineering myself; Thinking about engineering while I'm in the bathroom...

You get the drift.

Thanks for the new video!


Dean


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## SBWHART (Feb 25, 2010)

Deanofid  said:
			
		

> It runs just fabulous, Stew! One of the best Elbows I've seen yet.
> 
> Well... Maybe this will give you an idea. I do some potty engineering myself; Thinking about engineering while I'm in the bathroom...
> 
> ...



Ok we're talking about a chamber pot what they used before indoor plumbing I think I can work out the connection.

Boy you can get yourself in some real trouble with our "common language" what you call an erasure we call a rubber, that could result in a slapped face or a baby :big: :big: :big: :big:

Have fun

Stew


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## zeeprogrammer (Feb 25, 2010)

Nice Stew. Beautiful work.


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## vascon2196 (Feb 25, 2010)

Great job...wanted one since the minute I saw it.

Chris


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## Stan (Feb 25, 2010)

Another contradiction in our common language. What we, in North America, call a 'tart' is a small pastry.


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## rake60 (Feb 25, 2010)

Great video Stew! :bow: :bow: :bow:

I know from experience what is required to make an Elbow Engine run
effectively at low speeds. That is a very impressive build!

Rick


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## ChooChooMike (Feb 26, 2010)

:bow: :bow: :bow: 

Very very nice Stew !! Love the video too 

Mike


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## arnoldb (Feb 26, 2010)

> No the magic powder was just John's skill and knowledge in getting the best out of these little engines we make.



Thanks Stew  

 :-[ I over-complicated things - once again... I know from some personal experience that John does not care much for adulation, but credit where it is due ;D - So Cheers to *both* John and yourself then! :bow: :bow:


Kind regards, Arnold


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## SBWHART (Feb 26, 2010)

arnoldb  said:
			
		

> Thanks Stew
> 
> :-[ I over-complicated things - once again... I know from some personal experience that John does not care much for adulation, but credit where it is due ;D - So Cheers to *both* John and yourself then! :bow: :bow:
> 
> ...



Thanks Arnold

You were on the right track when you said graphite in fact the correct lubrication pays an important part in this engine, its very greedy for oil and it likes oil thats of a sticky grande, I think it helps forms a seal and cuts down air loss. One thing John did was to flush the engine through with alternate short runs on engine oil flushed out with a run on WD 40 he did this a couple of times, for the final run, that we videod, he used a different oil I think it was slidway oil.

The other thing he spotted was that I had a little bit too much play on the cylinders they we lifting up and leaking air, we just skimmed a couple of thou of the length of the axle pins, which had a big effect. One of the things I changed on the design was the axle pins, the new design allows easy fine adjustments.

I ran my engines this afternoon to entertain our daughter, she's three days over due to give birth, and feeling a bit fed up, I thought it would cheer her up a bit:- any excuse, the elbow performed great, the only thing that went wrong was that it sprayed my mother in law in oil:- be accident of course 

 Rof} Rof} Rof} Rof} Rof}

Cheers

Stew


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## SBWHART (Feb 28, 2010)

I'm going to try and get No1 Elbow running as good as No2 its got a falt with the fly wheel it wobles due to the hub being cracked so thats going to be replaced, I've had a good think and a tinker and I think the reason no 2 runs better is that I made the cylinder using the method outlined in the plans attached.

Now for the plans, I think the plans available over simplyfy the design requirement of the engine, this imay be reason people strugle to get a runner, with the drawing I've tried to capture my own and John's experiences in getting a successful engine built, these plans may have gone the other way and overcomplicated things the optimum design may be between the two.

I hope these plans stimulate some of you guys in having a go and successfully build an engine.

Good luck

Stew




View attachment Potty Elbow Plans[1].pdf


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## SBWHART (Mar 2, 2010)

Hi Chaps

First an appology to any one whose down loaded the drawing, some of the notes on sht 1 and 2 are very badly writen, I didn't proof read the drawing before I posted because I was tearing my hair out trying to save a good pdf copy of sht 5 on the cad system the drawing is fine but when I safv it to a PDF it misses great chunks out, I was messing arround trying to get it sorted for best part of a day even resorted to completly redoing the drawing, in the end I just posted what I'd got out of frustration, perhaps some of you computer Gorues know what hapening.

I've since sorted out sht 1 and 2 attached but sht 5 is beating me.

Any way as a bit of therapy I've made the new cylinders for the rebuild of No 1 and thought I'd share my method with you so her we go:-

Skim up a 2 1/4" length of brass enough for two cylinders and face and part off.







Grip in the chuck and get running true this is not to critical within a couple of thou will be fine.
Face up, Turn step for fly wheel, centre drill and drill right through with a letter D drill 0.246 dia.






You can do the next bit with a rotary table similar procedure, but I'm going to take advantage of the Pitch Circle Feature on my DRO so:-

Keeping the job in the chuck transfer over to the mill, centre the hole with the quill using a centre.






Clamp chuck to table.

Set up the PCD feature on DRO






Centre drill then drill letter D right through, the key to drilling long holes straight is having a machine with good bearings, a nice sharp drill, and not forcing the drill through take your time keep clearing the swarf, if you force it the drill will wonder.






Keeping the job still in the chuck transfer back to the lathe, face and part off:- dont forget to mark the cylinders so you can assemble them in the same orientation as they were drilled.






Face to length and chanfer the out side face.






Run a 1/4 hand reamer through to size the bores this will just take a whisper off.






Her they are done






And with the bling I've got no 1/4" balls for the shells.






Cheers

Stew 

View attachment Elbow Sht 1-Model.pdf


View attachment Elbow Sht 2-Model.pdf


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## Maryak (Mar 2, 2010)

SBWHART  said:
			
		

> I've since sorted out sht 1 and 2 attached but sht 5 is beating me.



Stew,

I use turbocad but I have had a similar problem trying to create a pdf. If I converted the drawing to DXF format the pdf was terrible. If I converted the drawing to Autocad 2000 I had a better result.

In Turbocad the native option is to print to Acrobat pdf from paper space. Another option may be to use Acrobat distiller to capture your page and third print from paper space as a jpg file and convert this to a pdf.

Hope this helps

Best Regards
Bob


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## SBWHART (Mar 4, 2010)

Bob

I,m using a copy of autocad 2008 don't ask where it came from :

Thanks for your advice Tried as you suggested but no joy, even tried copying it to power point which it did fine then saving that as pdf but it wont play.

Any way Rebuilt No1 with new cylinders and fitted a new hub in the flywheel its now wobble free.

And its a nice runner as well, remaking the cylinders did the trick.

Here's the video:- 

[ame]http://www.youtube.com/watch?v=Z1IbkYs2KTI[/ame]

I'm going to have to look arround for another project now.

Have fun

Stew


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## SBWHART (Mar 26, 2010)

Just a quick up date with some experiments I've been doing with lubrication 

Its been noticed by quite a few builders that elbows are quite fussy as to type and grade of oil you use, they like quite a thick oil and plenty of it, 3 in 1 oil is no good for them, I've tried quite a few different grades some they like some they don't, just to illustrate how fussy they can be I used a synthetic oil for diesel engines this stuff slowed it right down, one quick squirt of WD 40 and it speeds away, two squirts and it stopped dead.

Any way got hold of some Millway 68 slideway oil from RDG http://www.rdgtools.co.uk/acatalog/Coolants_and_oils.html

I've just ran my engine on this stuff for over an hour none stop, (still going) as far as Elbows are concerned it's better than sliced bread. :thumbup:

Cheers

Stew


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