Author Topic: Pennsylvania A3 Switcher (Kozo)  (Read 368911 times)

Online Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #2550 on: March 15, 2023, 11:38:00 PM »
After reassembling the boiler, remembering to include the firebox this time, I cut a strip of 1/8” copper to use for the left and right sides of the foundation ring.


After cleaning it up to the widest point on the sides, I cut that piece in half to make two pieces – one for each side – and set about shaping them to fit.  The only thing novel or interesting in this process is that I had to cut some relief for the blowdown bushing on one side.  I did this by using some sharpie around where the bushing was, then setting the foundation ring section in its place and raping it with a softish hammer.


This put a mark in the blue sharpie where it hit the bushing, showing me where I needed to remove material.



After I was satisfied(ish) with the fit, I marked and drilled holes for the hold-down screws – the same way as before using a combination of hand drill and mill -   then mounted them in place.


I’ve only got one section remaining. This will be the most challenging piece because of its weird shape. But I’ll tackle that tomorrow.

Progress…
Kim

Offline crueby

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #2551 on: March 15, 2023, 11:53:31 PM »
Looking  great!  When do the holes for the  stay bolts get drilled, before  or after soldering  the firebox  in place?

Offline Prowler901

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #2552 on: March 16, 2023, 03:15:04 AM »
Looking Good, Kim.  Next up...  The funky one.

Todd

Online Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #2553 on: March 16, 2023, 04:30:21 AM »
Looking  great!  When do the holes for the  stay bolts get drilled, before  or after soldering  the firebox  in place?
Kozo has you drill them AFTER you solder the firebox together.   So, after I get the foundation ring completed, I'll:

1) Solder the foundation ring pieces to the outside of the firebox & throat sheet, and to the backhead (with the backhead still detached)
2) Assemble the firebox and tubes, and backhead into the boiler shell & firebox sheet, and solder it all to the inside of the foundation ring.
3) Solder the throat sheet and backhead stays
4) Drill for the side stay bolts and solder them into place - outside first, then inside.
5) solder the front tube sheet into place

And there you have it, all done!

So close, and yet, so far...
Kim

Online Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #2554 on: March 16, 2023, 04:31:42 AM »
Looking Good, Kim.  Next up...  The funky one.

Todd
Yup, the funky one.  This is the price I pay for my stupidity. (Or lack of experience as I call it when I'm feeling more emotionally stable  :Lol:)

Thanks Todd!
Kim

Offline Michael S.

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #2555 on: March 16, 2023, 09:20:43 AM »
Kim, I think you can be proud of what you've accomplished so far. I myself have not yet gotten involved in such an extensive boiler project and therefore bought the boiler for my 5 inch locomotive.
Because I know how difficult this job is. But you did it and you will succeed in the last step.

Michael   :cheers:

Online Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #2556 on: March 16, 2023, 04:39:03 PM »
Thank you, Michael!
I'm feeling pretty good about it at the moment.  But as you know, this has been quite the rollercoaster ride for me  :insane:

Kim

Offline ddmckee54

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #2557 on: March 16, 2023, 06:13:33 PM »
Kim:

Won't where you had to recess the foundation ring to fit around the blow-down fitting leave a weak spot in the foundation ring?  Or is that ring so narrow at that point that it won't really have any effect?  Just wondering, because it looks like a significant part of the ring's thickness was removed. 

Don

Online Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #2558 on: March 17, 2023, 04:02:49 AM »
Interesting point, Don.
I believe it must be plenty strong because that's what Kozo shows to do in his plans.  It is documented that way.

The ring is 1/8" thick but most of the boiler is only 0.080" thick copper. And the tubes are only 0.062" thick (by plan).  So I believe that what remains in that one area is still plenty thick enough for safety.  Plus, as you say, it is only a very very small area that is that thin, so even at 160 lbs/in^2 (which is 2x pressure) that's going to be a fairly small amount of force.

Plus, it is being supported by the bushing itself.  At least, the way I did it, that cutout rests directly on the back side of the blowdown bushing.

This is my thinking anyway.  And what the plans show.  So hopefully, OK! :)
Kim

Offline john mills

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #2559 on: March 17, 2023, 07:54:49 AM »
in that area  when you heat it the silver solder should run in and it will all become one piece if you run enough solder in.
john

Offline Roger B

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #2560 on: March 17, 2023, 06:42:16 PM »
Some interesting challenges however you are meeting them  :)
Best regards

Roger

Online Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #2561 on: March 17, 2023, 11:11:58 PM »
Thanks Roger!

in that area  when you heat it the silver solder should run in and it will all become one piece if you run enough solder in.
john
Agreed, John!  I believe that is what will happen! :)

Kim

Offline samc88

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #2562 on: March 17, 2023, 11:13:49 PM »
Looking very nice so far Kim

Online Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #2563 on: March 17, 2023, 11:19:17 PM »
Thank you Sam!  :cheers:

Yesterday was domestic duty day, so no progress.  But today, I did get some shop time to work on that last section of the foundation ring.

I debated on how to go about this one and finally came up with this idea.  I made a template out of a piece of cardboard (like the kind that is the backing for a tablet of paper).  To do this, I used a large blue sharpie and colored the top of the inside of the firebox.


While the sharpie ink was still wet, I placed the cardboard on it and pressed it down firmly all across.  I actually used a little hammer to get a good impression.


Here’s what it looked like:


Using an X-Acto knife with a fresh blade, I cut out around the OUTSIDE of the ink impression. Then I inked up the outside edge of the firebox and, lining the cutout with the now cut outline, I made an impression of the outside the same way.  It now looked like this:


After cutting along the INSIDE of this ink impression I had my temple, and it (mostly) fit in the hole!


I then sprayed the back of the cardboard template with spray glue and placed it on my copper blank.  I had considered cutting the shape by filing, but after looking at how much copper needed to be removed, I decided to start with a little milling.  Here it is, set in the mill vise.


And after a few minutes of etch-a-sketch milling, I had this.  Lots of little stairsteps.


Now, to the files where I evened out those stair steps to make things mostly match the template.


Now this got me close-ish, but I still had a lot of filing and test fitting to go.  Like an hour and a half worth of filing, testing, bluing, sanding, etc. At which point I had this:


Not perfect, but pretty good.  Good enough that I can make it work. And this certainly was the hardest of the sections to make!

I did the mounting screw holes the same way as the others and here it is mounted in place:


Now I have to solder the whole thing together.  But that’s another day’s task.

Thanks for looking in,
Kim

Offline crueby

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #2564 on: March 17, 2023, 11:45:52 PM »
Looking  great!  When do the holes for the  stay bolts get drilled, before  or after soldering  the firebox  in place?
Kozo has you drill them AFTER you solder the firebox together.   So, after I get the foundation ring completed, I'll:

1) Solder the foundation ring pieces to the outside of the firebox & throat sheet, and to the backhead (with the backhead still detached)
2) Assemble the firebox and tubes, and backhead into the boiler shell & firebox sheet, and solder it all to the inside of the foundation ring.
3) Solder the throat sheet and backhead stays
4) Drill for the side stay bolts and solder them into place - outside first, then inside.
5) solder the front tube sheet into place

And there you have it, all done!

So close, and yet, so far...
Kim
Got it!  So any drilling chips from the stay bolts can be dumped out the front before the front tube sheet goes in.

You are getting good at making those foundation ring shapes, at least you are making it look easy!   :popcorn: :popcorn: :popcorn:

 

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