Marcher twin cylinder marine steam

[Team ricky]

Here’s the boiler ready to silver solder

A friend on the trade is going to solder it all up as I’m not well enough for fumes masks and all that !

The boiler is a mix of two designs which have attributes Im looking for , The boiler is a Babcock style with the added vertical flue tubes through the boiler shell, The idea is to have a central flue mounted on a flue cowl (low profile) I should get a lot of steam with a number 12 jet on a Bix style ceramic burner which I’ll make myself and test.

The boiler working pressure will be 50psi so a test at 120 psi should be good 😊

[Team ricky]

Hi Z,

Yes it’s a cork surface I like it because if I do wood bits I can pin to the bench and it’s easy to peel and replace !

The boiler is 2 3/4” diameter x 6 “ long

I haven’t calculated anything so just going on gut feeling really , which is where I get the most fun in hobby’s ….. I have also a quiet large Scotch return boiler with super heated manifold and wet steam manifold, That particular boiler can make a lot of steam but definitely requires a feed pump to get a good run time .. And a good amount of gas !

[Zephyrin]

nice to see that you are experimenting a personal design for a boiler...
Some years ago, I helped about half a dozen of friends with the brazing of their marine boiler, mostly of the internal butane flue tube type with water tubes in helical array crossing the flue, a very common design here; only 2 departed somewhat from this design.
I stopped this activity with the years (77 now) as brazing becomes too stressful, now, I simply discuss about steam around the pond (and at the bar too)  with modelers...just like in the forum !

[Team ricky]

After a bit of distractions elsewhere I did get on and make and eccentric!

A bit tricky in stainless 316 on my machine but it did do a good job 👍🏼

[Team ricky]

Hopefully the boiler has been pushed on a bit this week Silver soldering is the part a friend is helping with!


The engine I’ve done quite a bit more on , Made the eccentric’s , the straps completely, the eccentric rods and offered up the steam chests!

I thought to make a little registry lug from copper, form to the centre port and have it proud to engage the cylinder block port, That way I can pre-drill the chests and line them up and transfer punch the 4 holes perfectly !

[Team ricky]

A little more done today

It was more of a go over job ! I got the two marcher engines part way completed but decided to build a bigger Borderer from start to finish, After completing the crank for the bigger engine and spending a good amount of time dialing the crank during build I thought I better check the other smaller cranks and they were off by a fair margin, too much , so I decided to try and rescue the parts !

I was lucky because the error was the tail stock pressure which caused the output ends to be out so I tweaked the webs exactly at the roots to straighten them both ! Got 0.01 -0.02 , span them up and they are good ! Not perfect like the big crank I made but the fly wheels are steady and look concentric !

The bearings are good with no tight spots so I think I’m good ☺️

[Team ricky]

Here’s the crankshaft being Nickel plated just using house hold parts !

There are some YouTube vids on it and most just use:

Cheap mobile phone charger
Distilled white vinagar
99% pure Nickel
Salt

Pretty much what’s needed

I’ll post a pic later when it’s cooked long enough !! Around 2-2.5 hrs should be good 😊

[crueby]

Recently I've found that agitating the solution to keep the bubbles moving helps get a smoother surface, either tap on the container, or use a little submersible fish tank pump. Dont leave it in too long or it starts to get wrinkly.

[Team ricky]

Here’s the plating done ✅

[Team ricky]

A little more done ✅

Does not look like much but both big end brasses are made and fitted! A good tight fit but spins freely so I’ll take that and make the rods next

[Team ricky]

A little more sorted

Made both con rods and made one assembly ready to fit !

[Team ricky]

I’ve managed to complete some more jobs

Set up the rods and tested turning over , one small tight spot but with luck will run in …. Not serious in any way

I made the eccentric links and set up both, drilled and tapped for the valve chests , Made the cylinder nuts

Pretty much everything big made now and just down to pipe work and gaskets !!

Hopefully I will be able to steam test on the weekend!!

[crueby]

Great progress!   

[Team ricky]

Thanks !

Quick question for steam ppl….

The ports of the cylinders are called out at 1/8 tall if you will with 1/8 spacing between them

The piston valve is called out to block in/out ports in the centre of travel so far so good

Then the eccentric is called out to have 1/16” offset gives 1/8” total travel per revolution…..

Why only open the ports halfway ??

Odd…..

Piston valve wear? High rpm ?

I’m stumped

[crueby]

Hard to say what was in the mind of the designer. Once the surface area of the exposed port reaches the area of the passage behind it, opening farther really doesn't do much since the passage will restrict the flow. On a small scale model, the ports/passages really dont need to be very large to run well. I like to run my engines slow anyway, and the needle valve on the inlet doesnt need much more than barely cracked open, even on my larger engines, to get a nice running speed. It would be different for running at really high speeds with a large displacement engine. Its one thing we've noticed up at the logging museum on the steam Lombard (full size engines, about 8" bore). We have the reversing link only over to the first notch, so the valve ports are not opened that far and close early, and we still only move the throttle lever a fraction to get 19 tons of log hauler moving at 4 or 5 mph, since it was designed to pull 20 or 30 tons of logs, and we are running with no load behind it.