Author Topic: A small cochran boiler  (Read 29763 times)

Offline joe d

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Re: A small cochran boiler
« Reply #105 on: September 27, 2016, 02:57:48 PM »
That's turning out great.

I'm looking forward to see what you come up with next!

Joe

Online Florian Eberhard

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Re: A small cochran boiler
« Reply #106 on: October 15, 2016, 09:43:09 PM »
Good Evening Everyone!

The boiler is coming along great! Your sheet metal work is definitely up to a locomotive! Do you have a particular one in mind to build?

Yeah well I have started drawing one in my CAD program a long time ago.
But it will be a freelance locomotive without a full scale model.
It will be coal fired, in Scale G (45mm gauge)
I have attached a picture of my construcion.

But now, lets talk about the progress on the cochran Boiler:
I first drilled a hole into the smokebox for the chimney. Since my biggest endmill has a diameter of 16mm and the chimney has got 19mm on the inside, I had to use my boring head for the finish.
The mounting holes were drilled with thelp of the flange.
Next up were blower and blast pipe. And I was thinking about it for a long time. The really good Idea only just showed up after I had made a blast pipe jet, which resulted in a new jet.
The jet has got three blower holes and in the middle there is a big hole for the blast pipe.
Sticking three drills into the blower holes clearly shows that they meet at a point above the blast pipe/blower nozzle.
The blast pipe and blower asssembly will be located in the smokebox like illustrated in the picture where you see the smokebox from the inside.
Then I made some flanges for connecting exhaust steam and blower steam line to the smokebox using the integrated dividing jig of my lathe spindle and a dremel (acutally dremel-like tool).
And finally on the smokebox, shown from both sides

Will be continued right away...
« Last Edit: July 16, 2017, 02:01:26 PM by Florian Eberhard »

Online Florian Eberhard

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Re: A small cochran boiler
« Reply #107 on: October 15, 2016, 10:08:07 PM »
To form the connection between Flange and blast pipe body, I made a small bending tool from a piece of wood since the 4mm tube will be quite difficult to bend around such sharp corners as required in the smokebox
To show where the tube will have to connect to, i have inserted two cylindrical pins into the connection holes.
Bending was successful, though I have realized that a tube bending tool should be on my todo-list aswell. The tubes then were silver soldered to the blast pipe body.

In the meantime, I shortened some M1.2 screws for the chimney flange to screw the flange to the smoke box.
And there is the blast pipe and blower assembly built into the smoke box after pickling.
The Door hinges are not yet finished, so I screwed them down to a piece of brass for finishing (first cutting off the excess material and then file the end into the desired shape)
And this is the point where I got sidetracked quite excessively. I realized that i cannot reach the rivets with a straight punch. I then decided to build a riveting tool like it is sold by ateliermb (a swiss guy) .
The picture shows what came out. (I am going to open a seperate thread about building it)
Now riveting in the inside of the smokebox was really easy and I am extremely pleased by the tool i had built.
(The shaft of the rivets was a little too short so the head is not completely formed. But that works good enough for this application)
And there you go, all the hinges riveted to the smokebox. I really like the result!

Cheers Florian
« Last Edit: July 16, 2017, 02:16:16 PM by Florian Eberhard »

Online b.lindsey

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Re: A small cochran boiler
« Reply #108 on: October 15, 2016, 10:50:43 PM »
Most impressive Florian, it just keeps getting better with each new update. Can't wait to see it in action now!!

Bill

Online Dave Otto

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Re: A small cochran boiler
« Reply #109 on: October 16, 2016, 12:03:37 AM »
Wow that looks nice Florian.

The rivet squeezer is also a beautiful tool; I really need to make something like that someday.


Dave

Online crueby

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Re: A small cochran boiler
« Reply #110 on: October 16, 2016, 12:40:42 AM »
The boiler is coming along great, also I am VERY interested in the rivet forming tool construction and use, as I have a project coming up with a lot of rivets! I have not seen a tool like that before.

 :popcorn:

Online Kim

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Re: A small cochran boiler
« Reply #111 on: October 16, 2016, 03:38:00 PM »
Wow Florian, this looks great, as always.  I've been following along since the beginning, though I haven't commented much.  But I just wanted to say, VERY impressive work.  And I too, am interested in your riveting tool.  I'd love to see how you made it, and see it in action.

Those look like copper rivets your using there?

Kim

Online Roger B

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Re: A small cochran boiler
« Reply #112 on: October 16, 2016, 06:34:32 PM »
Beautiful work, as ever  :praise2:  :praise2:

Do you have a G scale layout to run your Locomotive on? Are you going to insulate the wheels so it can be run together with electric locomotives? I had a couple of G scale garden lines in England but currently all my stuff is in the attic.
Best regards

Roger

Online Florian Eberhard

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Re: A small cochran boiler
« Reply #113 on: October 16, 2016, 08:45:26 PM »
Good Evening! Thank you everyone for the compliments!

Kim, you are right, i am using copper rivets. I once bought an unfinished locomotive project off from ebay and in the parcel there was also a box with approximately 500 copper rivets. That is even the reason that I started using rivets!

Roger, I don't have a layout (would love to have one though) but up to now i (almost) have no reason to have one. Though I still have an LGB Mogul on the shelf but never had the intention to run it (I wanted to build a livesteam copy of it. But that project is quite far away right now...)
I honestly didn't think about the insulation of the wheels yet. But that would be quite some effort to do it properly because the axle is not the only thing that conducts electricity (also the linkage which would have to run on an insulated pin aswell as it should not be possible that it touches the wheels in any position!)

I guess I am rather not doing that but maybe - who knows - If I have some good ideas coming up?

Cheers Florian

Btw: I just wrote the first (of two) part of the building log about my riveting tool : http://www.modelenginemaker.com/index.php?topic=6497.msg132888#msg132888
« Last Edit: October 16, 2016, 09:17:48 PM by Florian Eberhard »

Online Florian Eberhard

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Re: A small cochran boiler
« Reply #114 on: November 28, 2016, 09:16:06 PM »
Hello Everyone

Yeah i know, I was quiet for a looooong time (at least about that boiler).
BUT i only wasn't writing, the boiler was proceeding nevertheless  ;) ;D

You may remember my thread about making the square broach, now I guess it is more than time to show you what I made it for:
I needed some rotating latches to hold the smoke box doors closed. They started as a small piece of brass. The first step was drilling them.
Then I clamped them on a small mandrel (made from a hex head screw) to machine the step.
Finally this is where the square broach was used. Some filing after broaching the square hole and they were finished.
The handle is directly added to one end of the axle and I first machined the square onto both ends of a piece of brass rod and drilled a M1.2 threaded hole into them.
And the moment of truth: The latches go on the axle with a slighly snug fit - exactly as intended  :whoohoo:
The levers have been turned using a form tool (which is not easy because of the huge overhang of the small brass rod. I also broke off the first or the second lever and had to start again.
There you go, the levers are bent too now. But somehow they look out of scale compared to the rest of the boiler.  :rant:
So this is it for tonight. I will have to redo the handles, the Idea how they shall look is not yet here though..!  :thinking:

See you next time, Florian
« Last Edit: July 16, 2017, 02:21:18 PM by Florian Eberhard »

Online b.lindsey

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Re: A small cochran boiler
« Reply #115 on: November 29, 2016, 02:07:12 AM »
The handles look very nice to me Florian, but of course you are the one that needs to be happy with them. More great work on the boiler though. Thanks for the update.

Bill

Online steamer

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Re: A small cochran boiler
« Reply #116 on: November 29, 2016, 01:44:58 PM »
Hey Florian,

From a 12" to the foot scale, If I was firing that boiler perspective..............,

Opening the doors would be for clean out, and perhaps blowing/punching tubes

That said   I would make them small and fit close to the face of the door.   Simple handles

Additionally, again .....if I was swinging a shovel on that boiler in full scale, I'd want the handles as far away from the fire box door as I could get to avoid catching a shovel, or my shirt sleeves...or anything else on the handles...



...but that's just me......you own the Florian Cochran boiler company....build any way you like!!  8-)

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Online Florian Eberhard

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Re: A small cochran boiler
« Reply #117 on: November 29, 2016, 07:14:30 PM »
Hey Dave

You are talking about the same points I had in mind. The levers are too big and not close enough to the doors. Thats what i don't like about them.
I'll keep them until i have a better Idea how to make them and how they should look like exactly.

So whats next:

To keep the smoke box doors at reasonable temperatures, I decided to also mount heat reflectors on them. The reflectors are made from 0.5mm thick stainless steel sheet. Somehow there were no pictures around from making them. I then positioned them on the doors and fixed them with a little bit of superglue.

Then I took out my fixture for the doors (and made two clamps to hold the door-reflector sandwich) and drilled the mounting holes for the reflectors.
And once again, I made a mistake. The marked hole has a diameter of 3mm instead of 2.5mm. I have no Idea why i picked the wrong drill but that meant making a new door. The new door is already cut off from some 1mm brass (Above the ruler are the reflectors).
Drilling the new door went pretty fast since the fixture was already in the vice.
Meanwhile I used the crap door to test how to make the spacers between door and reflector. The attempt below was to rivet some nuts with a rivet-pin end into the door. Well that one did not work, you can see how the brass around the rivet head was distorted.
Now, I really did not want to have anything else than a rivet-head on the outside of the door. Finally I decided to make bolts with a rivet head and a conical section between thread and head so the bolt won't turn free when tightening. And that luckily turned out how I had imagined.
The bolts are held by some overlong nuts that I made. The reflector will then be fixed with anohter nut.
And again I made a mistake. The bolts are one millimeter too short..!  :facepalm: -> I needed to get some more sleep and after that everything worked again. Well - I should know that actually  :slap:

Ok, so much for now - I'll continue here a bit later.
« Last Edit: July 16, 2017, 02:27:08 PM by Florian Eberhard »

Online Florian Eberhard

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Re: A small cochran boiler
« Reply #118 on: November 29, 2016, 09:01:03 PM »
Back again!


I just took two more pictures from the doors, one with closed and the other with opened doors.

Finally the smoke box is done, lets see what there's left:

1. making the "foundation ring" (is that the right expression for it?)
2. finishing the reversing chamber
3. making new handwheels for the valves (since the wooden rings got loose - I've got to find another design..!)
4. shortening the chimney and probably make a ring for the top of it (I am not sure yet if I want one)
5. some pipework

I started off with the first task (thats why it has the numer 1  :LittleDevil: ). This hollow gunmetal piece was just perfect considering its dimensions. So I machined ID and OD and cut off a short ring. 
Once more I used my superglue chuck to finish the second side.
Drilling the holes was pretty easy with my dividing head. Just had to watch out to get the right divisions.
After drilling the holes on the flat part of the angle section ring, I milled off the excessive part.  Luckily I had to remove part of the ring because it had become loose when I drilled the second last hole (and the hole was a little egg shaped. The drill survived though). So for finishing I just clamped the ring down, since the forces were going to be rather low:
The last step was riveting the ring onto the base of the boiler. (I of course used my riveting pliers for that 8) )
And here is the last picture for this time: a preview on how the boiler will look finally:

Cheers Florian
« Last Edit: July 16, 2017, 02:32:59 PM by Florian Eberhard »

Offline Don1966

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Re: A small cochran boiler
« Reply #119 on: November 30, 2016, 12:35:58 AM »
Beautiful piece of work Florian....... :praise2:

Don