Author Topic: Are metric plans for the Stuart beam engine available?  (Read 893 times)

Offline Gas_mantle

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Are metric plans for the Stuart beam engine available?
« on: April 07, 2023, 12:49:25 PM »
The title says it all really.

I have just bought a set of castings for the engine, the set came with the plans and the building guide book. Both are imperial measurements only and the plan sheets are difficult to read due to age wear and fading. I appreciate i can convert all measurements to metric myself but it makes sense to try and buy metric plans if they are available.

Can anyone point me in the right direction?

Offline simplyloco

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Re: Are metric plans for the Stuart beam engine available?
« Reply #1 on: April 07, 2023, 03:17:55 PM »
I've never seen any models of that era presented with Metric drawings, so I fear you will be unlucky.
Strong minds discuss ideas, average minds discuss events, weak minds discuss people.” ― Socrates

Online Jasonb

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Re: Are metric plans for the Stuart beam engine available?
« Reply #2 on: April 07, 2023, 04:06:12 PM »
The 10V is the only Stuart I know of that has published metric drawings.

I have quite a few of the common parts that the other 2" x 1" engines use modelled in metric and not just a mathmatical conversion eg my cylinders are 50 x 25mm not 50.8 x 25.4mm but I would want to draw the whole thing up to check it would go together before letting anyone else loose with a partial unchecked set

Did you get a full set or just the castings that had long since parted company with the barstock and fixings? If so then it's easier to change to metric stock sizes and alter the fixings. the 2BA look way too large so reduce to M4, 5BA to M3 and the many 7BA to M2.5 all with small hex metric nuts

Offline Gas_mantle

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Re: Are metric plans for the Stuart beam engine available?
« Reply #3 on: April 07, 2023, 06:07:18 PM »
Thanks guys.

Jason, I have the full set of casting but none of the fixing hardware. I'm not sure of the age but they appear old, the plans and guide book are faded and appear old - I'd guess they are 1970s but cant be sure.

Offline AVTUR

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Re: Are metric plans for the Stuart beam engine available?
« Reply #4 on: April 07, 2023, 06:24:34 PM »
I recently bought a set of castings for a Stuart compound marine engine as a “fill in” project. I have decide to make it metric as Jason describes and have started the drawings. Obviously there are a few changes that slightly worry me. However the main problem are the valve ports in the cylinder, these are obviously Imperial. Any changes to the valve gear need to be considered very carefully.

AVTUR
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Online Jasonb

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Re: Are metric plans for the Stuart beam engine available?
« Reply #5 on: April 07, 2023, 07:01:44 PM »
The compound is not too bad. Ports 5/64" = 2mm, 5/32" = 4mm both 6 & 11mm wide. Valve 5/16" = 8mm again 6 & 11 mm wide recesses, length 13.5mm for both. Eccentric offset 3.6mm is closest but 3.5mm will do fine if you want to keep to 5mm increments.

If you are running just for display it becomes even less critical. Take a look at the video of when I first test ran the Recent James Coombes - just screws poked into the valve linkage pvots, no gland packing or piston rings, bit of bar across the top conrod and crosshead guide and at about 25seconds in look at the nut on the end of the valve rod that came loose and I'm loosing about 1.5 to 2mm of valve movement  :facepalm:. If the engine is built well enough it will still run on a few psi of air

<a href="https://www.youtube.com/watch?v=1j3jl8lvWf4" target="_blank">http://www.youtube.com/watch?v=1j3jl8lvWf4</a>
« Last Edit: April 07, 2023, 07:20:27 PM by Jasonb »

Online crueby

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Re: Are metric plans for the Stuart beam engine available?
« Reply #6 on: April 07, 2023, 07:02:50 PM »
Jason, the video is marked private so we can't see it...  :(

Online Jasonb

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Re: Are metric plans for the Stuart beam engine available?
« Reply #7 on: April 07, 2023, 07:21:03 PM »
Try it now, it's "unlisted" but I had not clicked publish

Offline Gas_mantle

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Re: Are metric plans for the Stuart beam engine available?
« Reply #8 on: April 07, 2023, 07:26:14 PM »
Jason, is that a barstock James Coombes? Its a nice engine and something Id consider building after the beam engine.

Online Jasonb

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Re: Are metric plans for the Stuart beam engine available?
« Reply #9 on: April 07, 2023, 07:29:31 PM »
I did just use a modified cylinder casting but that could also be fabricated or cut from solid

https://www.modelenginemaker.com/index.php/topic,11255.0.html

Similar with the Real where I just used a flywheel casting and modified cylinder again

https://www.modelenginemaker.com/index.php/topic,10858.0.html

Online crueby

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Re: Are metric plans for the Stuart beam engine available?
« Reply #10 on: April 07, 2023, 07:36:33 PM »
Try it now, it's "unlisted" but I had not clicked publish


Great!

Online Jasonb

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Re: Are metric plans for the Stuart beam engine available?
« Reply #11 on: April 07, 2023, 07:59:06 PM »
Forgot to say that is running with the as cast valve ports, I did not even bother to measure them as they looked quite nicely cast. The real I did just have to even them up as they were a bit off. Main thing is to pick the sand out of the cored passages and you are good to go

 

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