PM Research Engine Number 1

[propforward]

Thank you! The shop itself has been a work in progress over the last 10 years. I’m pretty happy with it.

That is indeed a PMR #4. It’s a beastie, but I don’t think it will be any more complex than the #1. I was checking that my mill has the travel to handle it, which it does. But no starting it until the current engine is done.

[gary.a.ayres]

Nice...

It might even be easier because it's bigger.

Yes, wise not to start it till the #1 is finished. Something to look forward to. Also, you wouldn't want to be getting the parts mixed up between the two engines!   

I have a PMR #6 sitting as yet untouched. I bought it in a fit of inspiration a couple of years ago after seeing this:

<a href="https://www.youtube.com/watch?v=8FXeYKvQQ6o" target="_blank">http://www.youtube.com/watch?v=8FXeYKvQQ6o</a>

However, I decided I'd better start with a few 'barstock' engines as practice lest I destroy the castings. The uniflow is the second of these. To be honest, I'm now more drawn to making engines of my own design, but no doubt I'll get on to the #6 at some point.

[propforward]

Thanks for the link Gary.

Now I've got it into my head to build a boiler for my PMR #1. once it's finished.

 

[gary.a.ayres]

Ha, yes.

What type and size are you thinking of? A PMR kit, or your own design...?

[propforward]

I’ve ordered the book “model boilers and boilermaking”, I figured I’d start there. So not my own design, probably from drawings rather than a kit.

[gary.a.ayres]

Way to go, I reckon. And you can always make a few minor mods according to your requirements, which makes it your own.

The K.N. Harris book? It's very good, and is filled with hilarious old-school Brit pronouncements.   

[propforward]

That's the one! I was reading through the "boiler" forum last night, and that seemed to come up frequently. Looking forward to reading it - I do love an old school pronouncement!

[gary.a.ayres]

You are in for a treat, then!

What kind of size are you looking at?

[propforward]

Well I’m not totally sure, but from my little bit of readung it seems like a 3” boiler will run this engine, so that’s a good starting point, rather than immediately jumping at one big enough for the PMR #4. Keep the material costs down a bit. I was looking at your boiler thread last night, which I enjoyed reading again.

[gary.a.ayres]

Ha, yes - beset with trials and tribulations as it was!     I got there though...

Good idea to start smallish I reckon, so that by the time you get to building a bigger one you have some experience under your belt.

[gary.a.ayres]

One of the things on my long list (and believe me, it's very long) is an 8 inch version of one of the horizontal boilers in the Harris book. Steel barrel with copper tubes rolled in.

I already have the 8 inch steel pipe taking up space in my workshop.

An exciting but daunting prospect...

[propforward]

The funnest projects are always daunting at first! It’s good to have a long project list. Dreams are important. There is a steam tractor on my list - all these other engines are really just a roadmap to a traction engine. Maybe I’ll get there, maybe not. But there should be good scenery en route.

[gary.a.ayres]

Great philosophy Stuart.

'Good scenery en route' - I like that.

 

[propforward]

Progress! Not a whole lot - had to do a few other projects to help some people out. One of which involved me taking my first tentative steps in TIG welding, so still fun.

But, after that, got back to the engine.

Mounted my collet chuck back on the lathe, and worked on the crankshaft. Even got to use my recently made carriage stop, which was hugely satisfying.



Not great finishes.



Went to test it in the base casting - fits lovely - nicely held between the journals, and it spins a treat. Not too much play, spins freely. I am exceedingly happy with this.



Now I have to mill out the center support web and turn the big end journal. I am frankly nervous that the crank will move all over the place when I mill out the support, but if it does I'll just make a built crankshaft. I had considered making a support jig, and taking out the support bridge before doing any turning - but I've read some success stories with this approach, so I just went for it.

If it doesn't move too much when I take out the bridge, then I'll make a jig to hold it and turn that center journal.

Exciting, and I'm pleased with this. 

[gary.a.ayres]

Looking great, Stuart. It must have been a relief when you realised the fit was good and the shaft turned sweetly.

Fingers crossed that it doesn't distort when you mill out the support web.