PMR #1 - Finished

[vederstein]

It took considerably longer than I thought, but my PM Research #1 is complete (Video below the photos):

 

[pirmin kogleck]

heres mine

 

[Steamchick]

Vederstein, I don't like to criticize, but PM research are at fault: The flywheel needs a counterbalance weight to minimise the imbalance of the piston, rod, crosshead, con-rod and big-end masses. I simply hate manufacturers that sell kits that have not been properly engineered with a counterbalance cast-in to the flywheel. They make a lovely, well made model look "amateurish" when finished and running. But it is nothing you have done, following their instructions. Just their poor omission. You can add a balance weight, (lead and clay/plasticine for experimenting?) with a bit of trial and error, and reduce the imbalance oscillation considerably. Then the engine will be able to run much slower as well.
(Old man's rant finished!)
But a smooth runner all the same, which is proof of good machining and assembly.
Well done.
K2

 

[cheepo45]

Very nice!
I like the paint job.
Scott

 

[Steamchick]

My "less than perfect" table engine. I aspire you the quality you achieve Verderstein, but fail by a measure or 3!
K2

 

[pirmin kogleck]

Honestly, my engine can run on very low pressure,and very slow at aprox 50-60rpm. I domt see the need for a counterbalance on such a small model.

 

[vederstein]

I don't like to criticize, but PM research are at fault:

It's been some time since I've completed an engine. I'll freely admit this isn't one of my best machining jobs.

I'm fully aware it doesn't run appreciably smoothly, but that's ok.

If I was perfect, I'd have no reason to keep doing this...

Thanks,

...Ved.

 

[Steamchick]

OK Pirmin. Ved, Your engines are better than mine, but I try and balance them so they run slowly and smoothly. Just one of my little quirks, to improve my own sub-standard machining and assembly skills.
"Balancing" a steam engine (and any multi-cylinder engine) means getting both the valve timing even between the cylinders, and the mechanical balance, though it was just the mechanical imbalance that I could see was a manufacturer's fault with this one. If they had bothered, they would have cast-in a balance weight on the flywheel, and provided instruction about where to set it relative to the big-end. But manufacturers of kits are simply too tight on costs to bother.
As long as you are satisfied with the end result, I have no worries.
I spent 20 years getting my Moto-Guzzi to idle reliably... by NOT setting the carbs to be identical, as the V-twin had different characteristics of engine speed for each cylinder.. (firing 285 degrees and 435 degrees apart) - so maybe I have hang-ups about such things.
Looking forward to seeing the next builds!
Thanks for posting your engines,
K2

 

[packrat]

Steam engines take a long time to build, I have spent 3 years on one, {that was when I was working full time} and just worked
on it when I had time...

 

[Steamchick]

Speedy! I am retired but hardly find more time for modelling than when I was working...
" years have passed since I started machining castings for a water pump - still Work-in-progress!
A new boiler assembly has stalled - for 3 months - due to other boilers needed re-certification.
Too much ambition, too little application!
K2

 

[radial1951]

Vederstein, I don't like to criticize, but PM research are at fault: The flywheel needs a counterbalance weight to minimise the imbalance of the piston, rod, crosshead, con-rod and big-end masses. I simply hate manufacturers that sell kits that have not been properly engineered with a counterbalance cast-in to the flywheel.

Steamchick, with respect, that's a bit unfair. PM Research are not really "at fault". They are just providing a period-correct simple stationary steam engine model. I don't recall seeing such full size engines with a counterbalanced flywheel although there may well be some. Most basic traction engines and portables, for example, have plain spoked flywheels and even bent-from-round-bar crankshafts with no obvious attempt made to balance anything. Hence they gently rock back and forth when at work. Unfortunately, the model in the video is running way over scale speed which accentuates the imbalance. At 1/2-1/3 the rpm this would not be an issue...

 

[Steamchick]

Point taken. Though I shall try and balance my engines as they are not actual models of real engines but representations of type. - and I like them to run a bit smoother than the unbalanced "shake".
That is my preference, and I was simply expressing my opinion.
Hope I didn't offend? Sorry if I did. Not my intent.
K2