Stuart Triple new build

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Emers

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Hi Everyone
I am starting this thread to show the progress of my Stuart Triple Expansion engine build.
I am a semi retired machinist 71 yrs old still working part time I have been self employed for the last 31 years doing mainly jobbing work on the equipment I have a cnc toolroom lathe, american controller ProtoTrak a great machine and a Chinese Bridgeport copy which I have converted to 4 axis cnc with help from an electrical engineer friend who I helped build a small helicopter so he did all the electrical work on the mill. I am using Mach3 great for what I do. The Stuart has been started I have machined the base and will work up from there.
I am just starting my Stuart Triple it is a daunting task. I have built 3 steam models over the last 3years I get to run them on steam every month at our model club. I have put my efforts on YouTube emers steam models have a look and let me know your thoughts. I would like peoples comment as my build progresses. I have attached some pics of my progress to date.

20211123_131047.jpg
 

oldengineguy

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John: Thanks for the post on this forum. You have some impressive machinery and history. I have all manual knobs and levers and only have X&Y axis DRO on the mill. Auto mechanic by trade ,no machine shop training, all self taught, just a life long( 75 yr) interest in engines &machinery. Didn't get eccentrics finished to-day darned paying job got in the way, will finish tomorrow I hope. Colin:D
 

Emers

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Hi Colin
I know the feeling. I too, still do some paying work it pays for the hobby. What are you building at this moment.
I am self taught with regards all things cnc my younger brother is a great toolmaker who is great on cnc machining so he is my help desk.
Cheers
emers (John)
 

dnalot

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I like your style. Some people make a part and rush off to the next part before completing the first part. Yours is fully detailed and even painted. Looks like your a ground up builder. I generally start with the part I may not be able to make. I figure if I can't make it why go on. So far that hasn't happened.

I have a long winter ahead so entertain me with this build.

Mark T
 

Emers

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Hi Mark
Yes ground up seemed the way to go. I roughed the base leaving a small amount to get to final size painted the base (pressure pack green) then made the steel base so I could hold it easily on the mill to then finish machine to size all the sections which did not need paint on them. this worked great.
 

Emers

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Today I made and finished the main bearings. To get them as accurate and inline as best I could I machined all exterior sizes before I drilled & reamed the main crank holes. I made the keeps to secure the bearings, oil cups tomorrow. I made a small fixture to accurately position the bearings so they would be kept in line as this is absolutely the most important thing to get right at this stage. Next major thing will be the crankshaft I have purchased some 1144 stress proof steel from the USA as I could not source it in Australia. A very complicated part I have checked several posts on how to attack it will see how I progress over the next couple of weeks
Kit of parts.jpg
Main bearings before crank hole.jpg
Fixture for crank hole.jpg
Final Reaming.jpg
Base & Main bearings.jpg
 

oldengineguy

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Emers That 's the way I started on my triple. It was a partial kit started by a guy 40 + years ago many parts lost many parts poorly made. I got drawings & fittings from Stuart, Later into the build I got HP cyl and water pump. There were no cast counter weights for the crank so I made webs from cold rolled 1018 milled to a "proper" looking shape ,shafts are 0-1 tool steel pressed up and pinned, seems to work OK. The sole plate was badly machined so had to make oversize bearing blocks from 660 bronze to suit . Holes for standards were slightly off centre so they were opened up to larger size in correct location with end mill and standards made to suit .In hindsight this engine has taken much longer to build than if I'd bought the kit in the first place. By the way "paying work" is 1967 Triumph GT6 engine overhaul .Colin
 

kvom

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A premature notice, but a builder posted vids of his triples running on air on the MEM website. While many builders seem to have trouble getting these to run on air, he did a simple mod of putting a pair of very light springs on the valve nuts to keep the valves pressed against ports. He also used a fine thread on the valve rods to get precise adjustment of lead/lap.
 

sniffipn

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1637996766320.png

the split line on the bearing is interesting.
how did you do that please?
what are the benefits?
 

Mechanicboy

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A premature notice, but a builder posted vids of his triples running on air on the MEM website. While many builders seem to have trouble getting these to run on air, he did a simple mod of putting a pair of very light springs on the valve nuts to keep the valves pressed against ports. He also used a fine thread on the valve rods to get precise adjustment of lead/lap.
"he did a simple mod of putting a pair of very light springs on the valve nuts to keep the valves pressed against port" --> No need to change the steam engine..

To running test for each cylinder: Remove the two connecting rod to other cylinder who is not in use (due less load caused by friction), the cylinder who is under test/adjusting timing must have connecting rod to run the steam engine. Also you are adjusting/running the triple steam engine as if it were "one cylinder steam engine".

After each cylinder has correct timing and running test for each cylinder is done, mount all connecting rod and the two manifolds on place and the triple steam engine is ready to run. :)

Here are a ton of good tips in this link.. Stuart Triple Expansion Engine

Here is my triple expansion steam engine running at airpressure.
 

Emers

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Hi sniffipn
I do the step in the bearings so if they are ever separated they go back together and keep the same alignment. each bearing is numbered on each half and goes into the same position on the base so they can be removed and replaced each time. They are machined using the fixture shown above so they are kept exactly in the same alignment. The split line is done first then the outside sizes finished then using the fixture the holes are drilled & reamed.
Someone has mentioned running on air I will initially try running on air but intend to run on steam when finished. I am a member of the Sydney Society of Model Engineers we have open days each month where I run on steam. Our open days have been restricted due to covid but should return after Xmas for the general public to again attend.
 

Mechanicboy

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Someone has mentioned running on air I will initially try running on air but intend to run on steam when finished.
Emers..

When I adjusted the timing of my triple expansion steam engine one for each cylinder with 2 cylinders disengaged (two connecting rod not on crankshaft) and test drive in both directions in rotation with one cylinder during test then I had to use compressed air for practical reason: Do not burn on fingers of the hot steam machine and it takes time to fire up the boiler every time. It saves a lot of time and convenient.

I have not yet obtained the boiler suitable for the triple expansion steam engine.
 

Jeffro

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Hello Emers
Just curious if a problem with the kit supplied crankshaft.
As in post #6
Next major thing will be the crankshaft I have purchased some 1144 stress proof steel from the USA as I could not source it in Australia.

You should be able to make good progress in a dry shop with weather like this ( a hint of rain, floods ?) :).

Cheers
Peter
 

Alec Ryals

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"he did a simple mod of putting a pair of very light springs on the valve nuts to keep the valves pressed against port" --> No need to change the steam engine..

To running test for each cylinder: Remove the two connecting rod to other cylinder who is not in use (due less load caused by friction), the cylinder who is under test/adjusting timing must have connecting rod to run the steam engine. Also you are adjusting/running the triple steam engine as if it were "one cylinder steam engine".

After each cylinder has correct timing and running test for each cylinder is done, mount all connecting rod and the two manifolds on place and the triple steam engine is ready to run. :)

Here are a ton of good tips in this link.. Stuart Triple Expansion Engine

Here is my triple expansion steam engine running at airpressure.
The main wear on steam engines is the valve steam pressure keeps the valve against the valve port no need for springs
 

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