Bessy Tractors engine mark 2

bessytractor · Bessy Tractors engine mark 2

Some of you may remember seeing a build diary of a simple oscillating engine I made one week last year. This was a rather large and heavy single acting engine, and had quite a few problems with the original design. This included the fact it was only single acting so I decided to carry on with an improved version. This new engine is very similar in build, the main differences being its bigger than before, has the crankshaft running in brass bushing to reduce friction, and is double acting. Hopefully this one should chuck out more power and revs than the previous engine. Here are some pics showing how far I've got, having started last Friday.

heres a pic of the basic engine frame.

here is Mark 1 with its new bigger brother.

the brass bush the crankshaft will run in.

the cylinder and its trunnion bolt/spring assembly.

the engine so far.

rangerssteamtoys

Looks to be a good project, whats the cylinder bore and stroke?

Looks prett big, what kind of boiler(if any) are you going to use?

bessytractor

Mister Occlusion

Looking good. I wonder why double acting oscillators aren't more common. The one I've got goes great guns.

Cranko

bessytractor

progress update (about time methinks)

I've been beavering away in the workshop and FINALLY managed to get a crankshaft that actually runs ok. The first one I made was a sloppy fit in the bearings, due to the drill bit making the hole slightly eliptical. To get round this I put a bit of bar behind the engine frame like before and having put a oil hole on it the crankshaft spins quite easily. The crankshaft isn't as appealing to my eye as my previous disc wheel one, but hey we can't have it all. I couldn't make a disc one as the materials we had weren't big enough in diameter for it, so a fabricated one had to be made. the flywheel is the same as before, and I hope will keep it all going. I don't see why not, it did before. All that remains to do is make the piston and solder some pipes on and its done. A coat of varnish on the base will render it completely finished.

I did make one cock-up while making the crankshaft though. In its new format (with the bar behind it) I trimmed the excess shaft off only to discover I'd taken way way way too much off so a flywheel couldn't be put on. Result was a new one having to be made

The first pic shows the engine thus far. Second is the crankshaft. Last is a family photo.

johnreid

I find both to be quite impressive, good work.

SillyBilly

Looks nice & chunky, coming together great now!

Cranko

Coming on well

bessytractor

thanks guys, looking forward to running this one

yes they are very chunky, the smaller one is actually heavier than the new one, probably the heavy gauge base I put on.

bessytractor

finished!

Well not quite, theres the plumbing to go on, but that can wait. I had several attempts at finding the best way of making the piston, and eventually settled on a three piece set up, piston head, piston rod and big end all thread locked together nice and tight. Initially it wouldn't run, so I enlarged the big end hole by 0.5mm so it was a slightly loose fit and lo and behold it ran. Due to the better machining and bearing surfacing, it runs a lot better than my first one and is very smooth to turn over. It runs in both directions both on the top and bottom ends of the cylinder. A quick wipe with brasso sorted it out for now. Its going to be given to my parents for Christmas, I think they'll like it, it also means it won't be going far and I can finish it!

School ends tomorrow, so I doubt I'll get a film of it very soon, but I might be able to use the compressor at the railway on Sunday.

Thanks for all the supprt during this project. I'll post up a thread with my next engine later on, I started the third one half way through making this one!

TRAPPERKEEPER

Nicely done, what is the next engine you are making?

Sandman

I know it's just me, but I'd love to see that engine drive the mother of all flywheels.

Great work mate.

bessytractor

IndianaRog

BT, hefty piece of work there, congrats on finishing it up.

bessytractor

thanks Rog

toxx

... looks heavy-duty, no nonsense-like. It's gonna do the job! Thumbs up!

Supreme work, well done, mate!!!

SillyBilly

Very Well Done BT!

bessytractor

thanks

Reid

Wowsir, that's a hunk of a chunk of metal work!

Very clean and aggressive looking.
Yes, here's hoping you find that right big flywheel.

Beautiful work from fine thought. Kudos.

bessytractor

thanks Reid, I've only tested it in single acting mode at the moment. It runs like a storm at 40 psi but I shall have to wait until I've plumbed the two steam ports together for double acting to happen.

Mister Occlusion

What a beast!

Have you got a boiler sufficient for powering it?

bessytractor