Author Topic: Donkey Steam Engine (based on Wm Harris design)  (Read 2402 times)

Offline cwelkie

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Donkey Steam Engine (based on Wm Harris design)
« on: April 29, 2024, 03:22:55 PM »
From the Harris plans but smaller; 60% of the book's drawings.  I redrew the design in Alibre Atom3D to accommodate the smaller size and required changes.

The boiler is based on the PM Research 3" vertical kit with features moved around to suit, extra holes and bits.  The cylinders are 0.6" bore cast iron based on Elmer's designs for small slide valve engines.

Unfortunately there are a couple of "oddly shaped" teeth on the winch drum gears (they were cut as a pair) which is causing the noise from the front drum (oddly).  I think the gear centres may be slightly different allowing the rear drum to run quietly but the front one not so much.

In the end it's been a rather long, challenging and satisfying project (but for the gear noise and paintwork).  Now on to the next project whatever that might be.

Photo before paint with the "water tender" and a video running.
Charlie



<a href="https://www.youtube.com/watch?v=wfEgQi4KlVU" target="_blank">http://www.youtube.com/watch?v=wfEgQi4KlVU</a>
« Last Edit: May 01, 2024, 07:04:50 AM by Jo »

Online crueby

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Re: Donkey Steam Engine (based on Wm Harris design)
« Reply #1 on: April 29, 2024, 04:26:39 PM »
Beautiful!  Years ago I got that book and thought about scaling for the PM boiler, but its never gotten past that stage. Lovely!

Offline sid pileski

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Re: Donkey Steam Engine (based on Wm Harris design)
« Reply #2 on: April 29, 2024, 04:49:09 PM »
Beautiful work.

Yes, the gear sound is a little annoying. Can you "massage" the offending tooth(teeth??)

Seems to work quite well otherwise.

Sid

Offline Krypto

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Re: Donkey Steam Engine (based on Wm Harris design)
« Reply #3 on: April 29, 2024, 04:55:11 PM »
That's a really nice model!  The boiler seems to be sized well with the engine.
My Workshop Blog:  https://doug.sdf.org/

Offline Dave Otto

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Re: Donkey Steam Engine (based on Wm Harris design)
« Reply #4 on: April 29, 2024, 05:40:06 PM »
Nice work Charlie!

I started on one of these years ago and got the base and most of the winch parts completed. Lost interest in the project and ended up selling it to a forum member.
I do like the scaled down version.

Dave

Online Kim

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Re: Donkey Steam Engine (based on Wm Harris design)
« Reply #5 on: April 29, 2024, 07:03:42 PM »
Beautiful engine, Charlie!  Nicely done.  And great video too!  :ThumbsUp: :popcorn: :popcorn:

Kim

Offline Admiral_dk

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Re: Donkey Steam Engine (based on Wm Harris design)
« Reply #6 on: April 29, 2024, 09:04:21 PM »
Looks amazing and runs great  :ThumbsUp:

I do understand why you're somewhat annoyed with the sound of the teeth ....

Per     :cheers:

Offline cwelkie

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Re: Donkey Steam Engine (based on Wm Harris design)
« Reply #7 on: April 30, 2024, 12:00:31 AM »
Thanks everyone for the kind comments. I am happy with the overall size of this one - I can easily lift it by myself!

I did the unthinkable and used a little “run in compound” (aka, fine valve grind paste) on the drum gears.  It seems to have made small improvement.  The issue is due to a couple thin teeth so not a clearance problem; hoped too smooth over any “rough edges”.  If I get bored, could always make another set of gears.

Charlie



Online SteamR

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Re: Donkey Steam Engine (based on Wm Harris design)
« Reply #8 on: April 30, 2024, 03:22:23 PM »
Looks great. A nice model engine

Richard

 

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