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My version of Potty Mill engine

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David George 111/04/2021 20:13:29
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1547 forum posts
478 photos

Just finnished the valve section and eccentric and done a first assembly. I have changed a few bits to my liking to give it a bit more strength.

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David

Jim Nic11/04/2021 20:30:03
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321 forum posts
192 photos

Looking good David.

What's in the box on top of the valve chest?

Jim

Neil Wyatt11/04/2021 20:30:22
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18585 forum posts
723 photos
78 articles

Nice job, David.

Next decision - to paint or not to paint?

Neil

Harry Wilkes11/04/2021 21:06:12
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1099 forum posts
64 photos

Nice

Nigel Graham 211/04/2021 21:39:07
1398 forum posts
20 photos

That's an elegant machine!

David George 111/04/2021 22:12:50
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1547 forum posts
478 photos

Hi Jim the box is an exhaust with the outlet on the end. I have drilled the exhaust outlets on the top and cross drilled to end.

Not tried it out yet and have some finishing to do on edges and corners as well as lube bits and pieces then clean up the flywheel casting. I probably will paint it red.

David

Jim Nic12/04/2021 10:26:27
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321 forum posts
192 photos

Thanks for that David. One of the things I like about Stew Hart's designs is that they can be personalised fairly easily. I did a similar thing on my version but had the inlet on top and the exhaust on the side.

finished 6.jpg

I like your connecting rod too, I must bear that in mind

Jim

SillyOldDuffer12/04/2021 10:48:20
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7131 forum posts
1571 photos

David's PottyMill is better finished than both of mine!

Admittedly both were made for the learning experience, but I paid more attention to finish on the second. Perhaps I should make a third, or several...

blush

Curiously my rather rough number 1 runs noticeably better than engine number 2. I suspect it's because №2 is a tighter fit all round, and needs running in! I'm still slightly miffed the extra-effort version wasn't as good as the trainee bodge!

Dave

Hopper12/04/2021 10:57:39
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5427 forum posts
134 photos
Posted by SillyOldDuffer on 12/04/2021 10:48:20:...

...Curiously my rather rough number 1 runs noticeably better than engine number 2. I suspect it's because №2 is a tighter fit all round, and needs running in! I'm still slightly miffed the extra-effort version wasn't as good as the trainee bodge!

Dave

As Mr Harley said to Mr Davidson, a little extra clearance never got in the way.

I have the same problem: using toolmaker's clearances and tolerances and ending up with things too damn tight for real world conditions..

Hopper12/04/2021 10:59:06
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5427 forum posts
134 photos
Posted by David George 1 on 11/04/2021 20:13:29:

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Love the high-performance con-rod. You'll be able to flog the daylights out of the engine with no fear of that letting go!

David George 125/04/2021 13:57:39
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1547 forum posts
478 photos

It lives. I had the first run on my engine.

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I had it connected to tyre inflator, only 5 PSI and it runs great.

David

Steviegtr25/04/2021 14:02:14
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2009 forum posts
272 photos

Brilliant David. Nice job.

Steve.

JasonB25/04/2021 16:06:17
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Moderator
20443 forum posts
2267 photos
1 articles

That turned out well.

geoff walker 125/04/2021 18:32:40
449 forum posts
168 photos

Well done David top quality stuff.

Are you going to set it up with that boiler of yours?

Go on let's see it running on steam.

mechman4826/04/2021 14:53:35
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2898 forum posts
450 photos

Super job David; any advice on how you prepped the aluminium pror to painting... was the paint rattle can or mini spray gun ?

George.

David George 126/04/2021 15:44:01
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1547 forum posts
478 photos

Hi George. I used rattle can paint. First an etch primer then a primer followed by finnish coat with fine wet and dry between coats.

David

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