Elmer's Kimble engine

[spuddevans]

I've been quietly enjoying your progress on this build Arnold, and I have to say that I am really impressed with your craftmanship. Well done that man


Tim

[arnoldb]

Thanks Benni 

Tim, thank you ! 

  Well, the Kimble is a runner, but it didn't come without a fight  .  Actually I had it running yesterday evening, but I was too dog tired to get a video and shoot a couple of photos.

After I assembled the engine, I had some troubles with binding. 

The way the engine gets assembled is awkward to say the least, with a major fiddly bit being trying to hold the columns with the flywheel, main shaft and valve rod all in place and getting the column mounting screws in place from the bottom - all the while trying not to scratch things and damage the paint.  This played havoc with trying to get the bearing columns aligned for the least amount of friction.
If I can provide some advise in this respect for anyone contemplating a build of this engine: Make split bearing blocks! - You'll save yourself a lot of hassle.

I found another source of binding eventually; I couldn't figure out where it was coming from initially; the vane would "stick" on one side - even though I'd taken great care in keeping tolerances close but not tight.  I finally traced the source to the one crank arm on the vane shaft; it had a high spot on the rounding that I didn't file down far enough, and that was touching the base  at one end of the throw  - a quick lick with a file and some emery cleared that up.

Once I'd gotten all the binding sorted out, I connected it to air, and it would try to run, but only go through three or so revolutions and stop.  I tried upping the pressure a bit, and when I got to 30psi I stopped - I didn't want to blow off the perspex cylinder cover.  I traced the problem to the timing - and this part was definitely my own fault for messing with some dimensions on the rotary valve.  Earlier in the build I'd made a slot in the bottom of the valve to compensate for the holes that had wandered into the engine top - but I made that slot wider than the diameter of the original port hole.  As it turned out, the slot would very nearly connect both steam ports at the same time, but once I really fine-tuned the valve on it's drive arm, the engine started running.

OK, enough blubbering - some photos and a video   

I must say, this was a really fun build - even though it took me a lot longer than any of my other engines before to complete, and to see the engine running is a real treat!

  , Arnold

[Ronkh]

Believe me Arnold.

This is a treat for me! I have so enjoyed this build as I have your other ones.

Thank you!

Kind regards,

Ron.

Whats next?!!?

[Stilldrillin]

Ooohhh..... Arnold! 

That's a fine sight to see. Running so sweetly! 

Blummin, well done. 

Incidentally, I now understand how it works! 

David D

[sbwhart]

Its a runner 

Well done Arnold

Stew

[Rob.Wilson]

ABOOT FRIGGIN TIME !  



  Cracking job Arnold     ,,, great build thread well photographed ,,, Top job all round 

I like the colour combination 


Rob

[doubleboost]

Great job
Arnold
Runs very nice
Thanks for a great build log
I am going to build a small wobbler try a few small bolts
John

[millwright]

I sat quietly at the back and watched this one come alive, A lovely job Arnold and a nice runner. Looks like you could nearly blow it round. and your usual very informative build log. Thanks 
John

[saw]

Congrats, a masterpeace. I have with pleasure read your build log from the first time and this is something  s

[arnoldb]

Thanks Ron  - next is some tooling - an MT4 ER25 chuck and a MT4->JT chuck adapter  for my mill and a bench to mount my small lathe.

David, Thanks  - Glad you understand how it works now 

  Thank you Stew !

  Rob, thanks mate -  What are you up to 

Thanks John doubleboost  - the small bolts are not that bad; seems I'm getting used to them...  They can be annoying to drop though 

  Thanks John millwright.  It's _just_ too tight still to run on breath power; I hope it will run in a bit more and get there.

Thanks Benni  - I don't know if it really can be classified as a masterpiece, but thanks for calling it one!

 , Arnold

[DaveH]

Arnold,

Fabulous from start to finish, so well photographed and documented.

And the finished engine I'll go along with Benni - A Masterpiece. The perspex cover - what a beautiful touch.

You really are an inspiration to a lot of us Arnold
 
DaveH

[arnoldb]

Thank you Dave  - If I'm an inspiration, well, thank you, but that's passing along inspiration I gained from other people and having fun in the process
 , Arnold

[BillTodd]

superb

[miner49r]

Arnold,
  Finely executed. I was curious how well the Kimble would run with air leaking past the sides of the vane. You have proved it can be done.
Alan

[arnoldb]

Bill, Thanks 

Thank you Alan  .  Yes, it can be done, but tolerances are very close; between the relatively tiny air/steam passages feeding the engine and the comparatively "large" surface area around the vane, this was quite a difficult engine to build.  I took the time to really try to understand what would make it tick over, and I'll openly admit that it was more of a challenge to get going than Phil Duclos's "Little Blazer"!

 , Arnold

[rleete]

Arnold, everytime I start an engine I think will be different, you seem to jump in and make one.  Your results are far better than I can achieve at this point probably ever, so posting mine after you would be like showing off a child's fingerpainting after the Mona Lisa.

Would you please tell me what you are going to do next so I can avoid the heartache?

[arnoldb]

Hi Rleete.

I promise you; it's not intentional; I pretty much follow my heart on what engine to build next; the Kimble was nagging at me to get built for more than a year...

Please don't put your own work down - go ahead and build your projects and share them - nobody will think badly of your work, and others are always willing to add good suggestions as to how one can improve.  If you receive criticism, it will 99% of the time be of a positive nature - from someone truly willing to take the time and effort to type up something to try and help.
When I started out in this hobby, I was in constant awe at how well other people's work came out against my own feeble attempts, and that can be disheartening.  We all have to start somewhere - so back then, I made myself a simple promise; I wouldn't compare my work against that of others; I would just take on each project and build it to the best of my own abilities, and try and improve in areas that needs improving on each project.  I am, in fact, my own worst critic. 

As to the next engine, I'm getting in the mood for a bit of gear cutting, so it might just be the #5 Geared engine next - but there are other engine builds also clamoring for attention from my brain cell - both from Elmer and others...

 , Arnold

[nel2lar]

Arnold
I must say a fine fine show. I still have not made mine yet, but I hope that it is half as nice as yours. A very nice write up and machining. So much skill, just wonderful.
Nelson Collar
 

[arnoldb]

Thanks Nelson 

 , Arnold

[nel2lar]

Arnold
I've been watching you and you have my vote all the way. That was one of the most amazing builds so far. Now I think I will try. I just loved the acrylic side set it off just right. What a piece for display. If you have not noticed I am isostatic. Love it and great craftsmanship.

Nelson Collar
amazing wonderful job

[arnoldb]

Once again thank you Nelson 

I enjoyed building this engine very much - but found it to be the most challenging of the 16 engines I've built so far; even more so than Phil Duclos's "Little Blazer" and the Elbow engine.  When you build it, pay particular attention to keeping the engine block accurately flat and parallel, and the hole for the main shaft (the one to which the vane is mounted) absolutely square to the engine body.  The steam passages are small - at 1.6mm (1/16") - so air supply into the engine is restricted, and with the large "circumference" of the vane, a sloppy fit of the vane will result in a non-runner, as all air would just blow past it's sides; I shot for a 0.01mm (1/2 thou) closeness of fit on the vane, and the engine still needs a fairly thick oil (I use diesel engine oil) to help seal off blow-by.

All mating surfaces for the engine components need to be close-fitting and flat as well; it's impractical to use any kind of packing/gaskets as that would throw out tolerances, so all surfaces need to seal as well as possible without any packing at all.

Please remember that if you do make a "steam" engine with transparent covers, that it becomes unsafe to run on actual steam - its compressed air only.

Just build the engine methodically; this is one that can't be rushed, or else you will end up making a lot of parts more than once.  I got lucky on this build; the only part I had to re-make was one of the 2mm screws that I made for fixing the top to the block.

If you have any questions about the engine, please feel free to ask; I'm by no means an expert, but seeing as this engine is so rare, at least I'm in a position where I can can try and help where needed.

 , Arnold

[Brass_Machine]

ooooh... just caught up with this thread. Very nice job Arnold!

Eric

[arnoldb]

Thanks very much Eric 

 , Arnold