A Cracker locomotive

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sbwhart:
Looks good to me to Arnold :thumbup:

Hope you soon start picking up. :headbang:

Stew

arnoldb:
Ron, Dave, David & Stew; Thanks gents :beer:

:ddb: Feeling better, but had some social commitments that detracted from my shop time - but had a load of good fun with some mates.

This engine is taking on a life of it's own :palm: - I've started to deviate so far from the original plans that I'm pretty much making things up as I'm going along now :dremel:
Yesterday I turned up the crank-side cylinder head. There is enough space to add a pack nut if needed, but I decided to first try without one:

The piston followed next. On all the engines I've built so far, I seem to have made the pistons slightly too large, and they all needed a LOT of running to loosen up, so this time I went for 0.01mm under-size rather than my usual 0.005mm as a test; a new piston is easy enough to make. Threaded M2 through the centre and then drilled 2mm to half-depth to guide the connecting rod before parting off:

Also made a start on the connecting rod - just some 2mm brazing rod threaded M2 on the end with the tailstock die holder - and a small retaining plate. I was originally going for a full-blown cross-head, but with the cylinder head being fairly thick, I decided to try the engine as-is. The bits I ended up with yesterday:

And assembled on the cylinder:

Today I started by drilling the right-hand frame for mounting the cylinder block, and also increased the "bearing" hole for the engine in size; I want to add a bit of packing between the engine and the frame to minimise heat transfer from the engine to the frame, and I don't want the bearing part of the engine in contact with the frame:

Then I started off on the crank - just a bit of phosphor bronze turned down and parted through a bit to thickness with the 3mm centre hole drilled:

On to the rotary table on the mill, and a hole drilled for a press-fit crank pin and whittled away to leave a (to me) pleasing looking web; the original plans don't have a crank web, but it should help to balance the engine a bit as well:

Parted off, and it looks fairly presentable:

The crank is 4mm thick, so I drilled and tapped it for an M3 grub screw through the web - rather than using threads or retaining compound to fit it to the axle.

I was still busting my head on how to retain the cylinder to the block, and had all kinds of weird and wonderful and complicated schemes floating around my noggin... The block still had to have two holes plugged and that gave me an idea for a simple solution; plug the holes in the block, but leave the plugs sticking out to retain a spring... I couldn't find suitable spring wire, so I used some more brazing rod; it is actually quite springy - and after a flurry of activity pressing in the crank pin, turning up and pressing in the main bearing and a temporary assembly, I had the ugly duckling together - with the idler shaft and gear acting as an impromptu main shaft/flywheel:

:palm: Looks horrible :lol:, but I had to give it a test :dremel:
:ddb: Started right up and runs like a champ - without a decent flywheel and at a pressure below what my compressor's gauge can measure :ddb:
Please take a Dramamine before watching the video :coffee:

:D Gave it a blow on breath power, and it runs easily; so after a bit of cosmetic work, I think the engine will do :ddb:
:beer:, Arnold

DaveH:
Arnold,

Well that is damn good, :clap: :clap: :clap:

(me thinks your pressure gauge is duff !!) :lol: :lol: :lol:

Really great Arnold, fair zips along, :thumbup: :thumbup: :thumbup:

:beer:
DaveH

sbwhart:
Give that man a coconut

:clap: :clap: :clap: :clap: :clap: :clap:

I like that retaining spring, neat idea. :thumbup:

Well done

Stew

Stilldrillin:
:D :D Yeee HAarrrr! :D :D

Nice one Arnold! Well done...... :clap: :clap:

I can see that grin from here ! :thumbup:

David D

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