Marcher twin cylinder marine steam

[Team ricky]

Hi Chaps,

I’m new here and wanted to share a nice build log of two lots of twin cylinder marcher engines

[Admiral_dk]

Don't think that I've seen this design before - but happy to see more 

Oh .... and welcome.

Per     

[Team ricky]

So I’m planning on building one as a piston valve engine and one as slide valve 


Should be interesting to try both out , I have just looked through the drawings and the piston valve version is a bit sketchy, When I get into it I’ll post some pictures !

[Team ricky]

So as far as I can see on the drawing there are two options within the piston valve configuration,

This makes for interesting building when you don’t know this in advance!

This picture details how you are not going to build the cylinders and piston 😂

[Team ricky]

This picture shows how it is to be built, however not very detailed for the piston valve itself as it needed a re-design….

The right side of the cylinder chest is to be cut off entirely, then the steam will come into the top of the cylinder via a banjo bolt, Problem is as drawn in the first picture the piston valve won’t work as there is no steam exit provided for in the lower half of the cylinder-piston arrangement.

I have made the cylinder chest as per second drawing, Then made the piston valve from ground SS stock and modified to allow steam to pass through the centre of the valve to the top to allow for a steam exhaust.

[Michael S.]

Hello,
I don't know, but I can't see any fault with the piston valve in the first picture. I think both directions of rotation of the motor will be possible. It works with external and internal inflow with steam. With the lower variant, the overall length of the motor is shorter, which is an advantage when used in model boats.

Michael

[Team ricky]

A bit more done today

I have made both identical piston valves with the hole down the centre to allow steam from the lower port to exit or feed as needed!  The last process is to drill a cross hole 1.5mm below the lower port position…

I also made a nicely fitting piston from phosphorus bronze with graphite yarn for the ring….

[Zephyrin]

but I don't see the problem you raise with the valve !

The only point I dislike with such a design is the lack of lap for the valve, required for the reversal of the rotation by inverting exhaust and steam intake, common in model engines but not very realistic, contrary to the slide valve version of this engine !

[Team ricky]

Hi,

Yes I see I didn’t quite catch all of the drawing!

The picture of the valve shown is good for making a part but isn’t suitable for the valve chests in the revised piston valve assembly, there is a picture of the correct valve but no dimms, and missing the cross hole ! It’s pictured inside the valve body and not separately to make it obvious there is a difference!?

Also made two piston rods and a cross head

The standards probably should be properly de-burred after the slots were cut as there are some small high spots inside, caught me out and I made the first one under size…

I’ll probably re-mount in the lathe, clock in, and very lightly skim with a boring bar …..

[Roger B]

Excellent work  That's not an engine I have seen before. Is it a US design?

[Michael S.]

Hello Roger,

I believe the castings for the steam engine can be purchased from Reeves.
I also wanted to build a small engine like this for a second steamboat. With a valve for reversing.
But then I found a German blueprint and then built this engine.
(At some point I'll change the many pipes. I think I can reduce that.)

Michael

[Team ricky]

A bit more underway

I got very distracted with building a boiler and a small oscillator engine !

I’m starting on the hardest work on this one ….. being stainless steel eccentrics 

[Team ricky]

And the boiler bits thus far

[cnr6400]

 

[Zephyrin]

good start with the boiler, bended tubes look fine.
what is the size of your boiler ?
2 double-acting cylinders make an engine thirsty for steam !
I saw a boiler plan in Model Engineer a long time ago; by J Bertinat, who designed the Marcher engine. I will look for references.
 
are you working on a cork surface on the workbench ? it looks so