the cringle engine. virtical steam

[darwenguy]

Hi all this is my first real go at making a working model its my own design of a virtical steam engine using common slide valve setup. It's been a steep learning curve so far learning to make wooden patterns making sand molds and casting aluminium and brass. I've made it quite a large model so that I can use standard cheep metric fasteners ball bearings and silver steel. Bout £100 in so far including making my furnace and patterns the rest was scap. I've got abouts 8 weeks in it so far from pen on paper most of that time spent making the patterns it's not really a scale model of eny real engine just my take on a stuart virtical made using my experience being a mechanical fitter working a on large industrial machines and everything I've learned reading this forum ta guys.
Just a few questions what are your opinions on my stainless steel cylinder liner?
Also would any one be interested in a set of drawings and castings at a resonate price it seams such a shame not to use my patters again. Sorry guys gramme is not my strong point any how some pics for you so far I shall try and take more pics of machining and casting now I have a new camera

 

[darwenguy]

 

[darwenguy]

 

[Herbiev]

Just wondering why the stainless steel liner. Must be a real pig for lapping.
As for sharing the castings I think postage costs would outweigh product costs.

 

[darwenguy]

I just used the stainless tube as it was what I had available and the aluminium is too soft just wondering why not many people use stainless I can machine it to a mirror finish
Also I added about 7% copper to the aluminium to make an alloy for the stand it's much harder and very nice to machine I would like to know more about this alloy please can't find much about it thanks

 

[cwelkie]

Thanks for sharing your progress so far. You have a lot to be proud of based on your results in a relatively short time-frame.
A very interesting design that is larger than many of the models se usually see.
Well done!
Charlie

 

[Blogwitch]

Great looking engine D.
I know what you mean about having stainless to hand, but in reality, cast iron would have been a perfect solution for the liner, as stainless has a very bad habit of galling when you least expect it.

PM sent.

John

 

[darwenguy]

hi thanks for the coments yeh cast iron would have been far better but only bit I have is 3 inch solid seams a wast. Il get more done tonight still getting the hang of casting brass you can see two failed gland followers in the pics. Il probably remake the con rod in ally as it's soo heavy. What would be a suitable piston with ss liner I've got some hard white nylon type plastic?

 

[Blogwitch]

If you are only going to run on air, then your white nylon should be fine, but do be aware that a lot of the nylons and plastics do absorb liquids and so 'grow' in size during their life, so do a bit of research first to see if your one has these tendencies as you will need to lubricate it at some time.

John

 

[darwenguy]

Cheers John il bear that in mine what do you think of an ally piston. Or should I use my nice bronze I've been saving.
I got a few hours in today made a crank pin and valve rod and brass bush. Done some fettling on the eccentric strap and found more slag porosity. This was cast in the same mold as the gland/flange castings so deffinatley a bad pour ordered some new crucibles and sand so I can have a play at melting cast iron

 

[darwenguy]

 

[Blogwitch]

Hi D,

Have a look at this chart, it should tell you which materials go well together.

I hope this helps

John

Please read your messages

 

[Jasonb]

Thats a very handsome looking engine and for a first casting effort you have done an excellent job.

I quite often use an aluminium piston in my steam engines, you should be able to cast up a simple blank, used with an O ring or traditional gland packing you should get a good seal. If running with steam allow for the piston to expand slightly into teh stainless sleeve, about 0.002" per 1" piston dia. Not used plastics for pistons but as John says some do swell up.

As for selling a few you may get some more takers on the forums that tend to have a few more UK members as postage is always going to bump the price up. Funny enough I was talking with someone who wanted a larger size engine recently but he settled on one of the bigger Stuart offerings.

J

 

[darwenguy]

Thanks john that chart is very handy. cheers Jason I may try an ally piston with orings i have plenty and it can go back in a melt if I mess it up. If I make it correct only the rings will contact the cylinder liner . Hope to cast the brass valve slide, glands and eccentric strap today if the rain stops

 

[darwenguy]

Still waiting on my crucible being delivered so i made the eccentric strap from brass bar stock. And made a eccentric from steel the bearing spins realy nice and free still nead to drill and tap for a grub screw. This will just be to get it running ive started drawing up a reverse linkage

 

[darwenguy]

Got more done this morning. Made the valve linkage. Finished fitting the eccentric and cast the gland followers and vale slide in brass. Oops i forgot pics again just one of the casting before fetteling. I should have it running on air in the next week just gland followers and piston left to make then lots of tool marks to clean up and polish and paint.

 

[Cymro77]

Very ambitious undertaking. Your appear to be doing an excellent job, thanks for sharing. Keep up the good work, I can't wait to see the end result.

 

[darwenguy]

Cheers cymro. Im still scratchin mi head over this reverse linkage i may recast the standard with some suporting brackets i want it to look well on the engine, any ideas? i realy nead to learn how to use cad or somthing simple

 

[Blogwitch]

Luke,

You have hit the main problem when designing and making on the run, modifications don't come easy.

Slip eccentrics don't really work too well with this size of engine (which could in fact be used do usable work), and your idea of going for a reversing linkage would be much better, but a lot more work involved.

Because you are now so far along with this version, and so close to finishing, if it was me, I would finish it off to prove the design, then do your second build with all the mods incorporated, otherwise you could end up chasing problems all along the build and it wouldn't end up like you really wanted it to.

It's looking really good BTW.


John

 

[darwenguy]

Cheers john i will be finishing this engine as it is. I ment il mod the pattern for the next casting, i could make brackets to mount on the steam chest studs but that seams a bit of a bodge to me