Chris's Mann Wagon Build

[crueby]

I have enough problem keeping up with wagon build let alone the pumping station!! Do you live on 1hrs sleep :-D :-D, beautiful workmanship i find myself looking forward to the pump now :-)

Going to be quite a while on starting the pump engine!

[steam guy willy]

Hi Chris , wow that looks like a project you really could have fun with. and ....if you do make two...Ill swop my electric boiler for one of them  ...???    interesting how the cylinder covers are all quite different. I do have a triple expansion set of castings myself actually..!!  but not in this class though..If you need to borrow my 14 and 16 BA taps and dies  ? that can be arranged !!

Willy....

[crueby]

Hi Chris , wow that looks like a project you really could have fun with. and ....if you do make two...Ill swop my electric boiler for one of them  ...???    interesting how the cylinder covers are all quite different. I do have a triple expansion set of castings myself actually..!!  but not in this class though

Willy....

So to get two now I need to make three... Going to be a busy spring!   


The cylinders for the hp and ip use rotary valves like a Corliss, the LP cylinder has poppet valves. All the valves are driven from eccentrics on a hear driven shaft up on the side of the engine, which saves space on the crankshaft which leaves room for the extra posts from the crossheads down to the pumps. Great engine design, just built REALLY big!


If you compare the cad drawing to the photo, you can see the cladding is not on yet. That shows the chambers used to buffer the steam between the cylinders. The cranks are 120 degrees apart.


Going to be a fun build once a lot more planning is done. Still a lot to do on the Mann truck: cab back wall and roof, transmission, crankshaft, reverse gear, compound engine, throttle and piping.

[MJM460]

Hi Chris, that is a really interesting approach to the check valves.  Obviously you don’t have a single ball for the check valve in this size.  The check valves I am familiar with have a cast flapper which is roughly disk shape.  It is not unknown for the parts of this disk to just keep going straight through instead of stopping at the seat as intended.  Newton’s laws in action!

I assume splitting the valve into many smaller ones, each with less weight in the disk and less travel, means there is less momentum in the closing disk, so less force when it hits the seat.  Probably helped with noise as well.

I can see the flange bolts will be an issue in keeping the model to a reasonable size.  It might possible to “ adjust” the flange dimensions a little to come up with a more practical bolt size.  At least the steam pipes could be modelled with insulation.  Perhaps noise insulation on the water pipes.  There is so much else to see on those engines, but at the end of the day too big is also a problem.

Something to ponder while the truck is completed.  We don’t want to miss the detail there either.

MJM460

[crueby]

Hi MJM,  you are right, these check valves are plates, held with coil springs. Designed big for large volume and long life. Those chambers look small, but the domes are around 8 foot across.




One thing that I am concerned about with going up in scale is boring put the IP and LP cylinders on my small lathe. Had an idea, what if I used a cast iron automotive cylinder liner/sleeve? Looks like they are available in a huge size range, price is not bad. Turning a stack of plates to make the outside of the cylinders on the faceplate would be doable, likewise the pistons.


 

[cnr6400]

Automotive cylinder liners would be a great approach to fab the big cylinders on the pumping engine. The outer cylinder blocks could be made of disks or a combination of disks and bent / cut plate silver soldered or bronze welded together. A guy who has published a lot in print and on line about his locomotive model cylinders made this way is Jan Eric Nystrom in Finland. Worth a Google. He has done some nice work, and certainly thinks "outside the box", coming up with great practical solutions to make things on his small-ish machine tools.

Another idea for cylinder liners - "non rebuidable" pneumatic cylinders have a thinwall cylinder tube which is beautifully finished inside. These cylinders are not expensive and available in a huge range of sizes. Often you can find new ones in surplus places and at auction sales. Bimba is one US made brand, and there are of course plenty of imitation ones of good quality available from the far east at a fraction of the cost of US made ones. Hydraulic cylinders would be another possibility but these are usually very thick walled and may require a lot of machining. There could be rebuild liners available for hyd cyls too, but I have never come across them.

For the poppet valves on the cylinders, it would save a great deal of work to adapt small 4 stroke engine exhaust valves for use as steam poppet valves.  These are available fairly cheaply in sizes ranging from about 1" head dia in mower engines down to about 0.1" head diameter in model aircraft 4 stroke engines. For example in my 4 stroke weed trimmer engine, made by Briggs and Stratton in 2002, the exhaust valve is about 3/8" head diameter. They see some rough very high temp service is I.C. engines, and are made of very good steel. Life in a slow speed steam pumping engine would be a like a vacation for them! 

[crueby]

Great tips CNR, will check them out!

[ddmckee54]

With the exception of the wet cylinder liners used in large diesels, most of the liners that I've seen used in engine repair still required you to bore the cylinder to the final size.

I take it that the LP cylinder is larger than you can line bore on your Sherline, even with the extender blocks?

Don

[crueby]

With the exception of the wet cylinder liners used in large diesels, most of the liners that I've seen used in engine repair still required you to bore the cylinder to the final size.

I take it that the LP cylinder is larger than you can line bore on your Sherline, even with the extender blocks?

Don

Do the liners come with a smooth enough bore to use for a slow steam engine, or are they rough?


The sherline could spin the block with the risers, but not over the carriage. The larger cylinder is just too wide and tall for these machines.

EDIT: did some more checking around, and it sounds like there are a number of brands of the liners for the smaller engines that come already bored and finish honed on the inside, but they can require boring the existing cylinder out to install them. In my case, making the rest from scratch, I would just have to match the OD with my cylinder plate stacks, as long as I buy ones that are honed on the inside already. Good to know, will look for that when I go buy them (which wont be for a while).   

[crueby]

And back on the steam wagon - remember the steam wagon?   

Been doing a lot of assembly and paint work, here are the cab parts so far - still needs a few touchups where the paint bled under the tape:

The black on the interior really sets off the outside colors. While the paint is curing up, I've started cutting down the boards for the roof and back wall panels. Also, need to make up some seat cushions for the cab. Since stitching that small is beyond me, and the elves flunked out of Jo's needlepoint class (the videos of thier night out drinking with Surus are pretty funny though), I'm thinking of carving them from wood - with old butt/back depressions shaped in, and the outside painted up to look like old leather.

[Craig DeShong]

“When I grow up I wan’na be able to paint like Chris” 

Beautiful work Chris   

 

[cnr6400]

What steam wagon? 

Just kidding - paint looks amazing! 

[crueby]

Very happy with how the paint is looking. Really tough to do. Shake can. Point it at the parts. Press button and move can side to side...      Masking tape is your friend!


 

[RonGinger]

Several years ago I built one of Ray Hasbroucks steam engines that was designed around a car engine sleeve. By the time I built it that car was long out of production and sleeves were no longer around. I went to a motorcycle repair shop with my mic and calipers and looked through their supply of cylinders- they had many smaller sleeves that would be great for models. I wound  up with a Triumph 650 sleeve. The kit included a sleeve, piston and rings. I used the sleeve and rings.

Have a look at a motorcycle shop, or maybe a small engine repair shop.

[crueby]

Thanks Ron! I'll give the cycle shops a look too. Getting rings with it must have saved you some work.

The shop elves cousin Ethan has come by for a visit (fresh out of the quarantine box they taped him up in out in the back yard), and he is just about the right size to help me mock up the steering wheel position:

At 8" tall, just right for this model, and proper outfit as well.