Author Topic: Pennsylvania A3 Switcher (Kozo)  (Read 316103 times)

Offline steamer

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #3690 on: February 07, 2024, 01:10:06 AM »
OOOOOOH that bell is so cute! :cheers:
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Offline tzkelley

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #3691 on: February 07, 2024, 03:30:34 AM »
That bell not only looks good but sounds good, too!

Offline cnr6400

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #3692 on: February 07, 2024, 04:20:36 AM »
 :ThumbsUp: :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :popcorn: Great looking bell Kim!
"I've cut that stock three times, and it's still too short!"

Online Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #3693 on: February 07, 2024, 05:31:07 AM »
Thanks, everyone!

Chris, there's only one whistle, and it's visible.  I don't know how it compares in size to the prototype, but it's only a few inches long and lays down along the top of the boiler close to the cab where you can see it.  It's not overly large so I imagine it will be a dainty little whistle to match the dainty little bell that it goes with  :Lol:

Kim

Offline gunna

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #3694 on: February 08, 2024, 07:46:14 AM »
Kim, when you get around to that pressure gauge, make sure you have the right character set in your printer for the dial!! I have always been intrigued by this gauge which is on one of the big diesels in our museum. I'm not sure if the reading should change along with the international exchange rate. :stir:
Ian.

Offline gunna

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #3695 on: February 08, 2024, 07:47:56 AM »
Other pic didn't come up for some reason.
Ian

Offline Michael S.

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #3696 on: February 08, 2024, 08:32:23 AM »
On the old pressure gauge I have, this old unit for the pressure is also written.
What does that actually mean exactly?
Our older technicians sometimes still speak of “Atü” (atmosphere overpressure) when the pressure is indicated on the manometer.

Michael

Offline uuu

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #3697 on: February 08, 2024, 09:23:08 AM »
I would read that as "pounds pressure per square inch", although I don't know what the little crescent under the inch symbol is. 

As for your overpressure idea - I can guess:  If you are trying to calculate how much mass of gas you have in a vessel, you'd need to multiply the volume by the pressure and some kind of density constant (molar mass).  There are online calculators.  But you need the "absolute pressure", i.e. the pressure above a vacuum.  So you'd need to add the atmospheric pressure to any reading on a manometer.

Wilf

Offline Michael S.

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #3698 on: February 08, 2024, 03:43:35 PM »
Absolutely correctly explained.
That's why the confusing unit of Atm / Atü has already been changed to Kp / cm°, then to kPa or Mpa for a while and now to bar.

Michael

Online Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #3699 on: February 08, 2024, 05:52:35 PM »
That's fascinating!   I can see the 'per square inch' part.  But in the pics posted by Ian, the $ doesn't make sense to me.  Dollars per square inch?  :???:

The pictures Michael posted have a character I'm unfamiliar with the fancy slashed U thing.  Does that mean pounds?  I thought the fancy L with a line through it was pounds? :)

I probably won't rate my pressure gauge in Atmospheres though.  I'll probably stick with the PSI units that I'm more familiar with.  :embarassed:

Kim

Offline uuu

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #3700 on: February 08, 2024, 09:19:46 PM »
That's fascinating!   I can see the 'per square inch' part.  But in the pics posted by Ian, the $ doesn't make sense to me.  Dollars per square inch?  :???:

Kim

I think it's a stylised "lbs"

Wilf

Online Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #3701 on: February 08, 2024, 09:56:44 PM »
That's fascinating!   I can see the 'per square inch' part.  But in the pics posted by Ian, the $ doesn't make sense to me.  Dollars per square inch?  :???:

Kim

I think it's a stylised "lbs"

Wilf
Ah... yes, of course, that would make more sense   :embarassed:
Kim

Offline jcge

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #3702 on: February 09, 2024, 10:06:08 PM »
Perhaps the Fabrik-Zeichen gauge's "U" is for "Uber" (over) pressure.
John

Online Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #3703 on: February 13, 2024, 10:13:33 PM »
Perhaps the Fabrik-Zeichen gauge's "U" is for "Uber" (over) pressure.
John
Seems like a reasonable guess to me! :)

Kim

Online Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #3704 on: February 13, 2024, 10:22:01 PM »
Chapter 29.6 – Bell Stand and Yoke

This week I’ve started the Bell Stand.  This is, of course, the part that will support the bell and hold it above the boiler in its rightful place.

Somehow in my BOM I’d set this part up to be made from steel sheet.  But I want it left bright, so it needs to be brass.  Consequently, because of that mistake, I didn’t source any appropriate thickness brass sheet.

So, I went scrounging around in my brass stock and came up with a 1/4" x 3/16” brass bar.  That’d work great since the bell stand needs to be 3/16” wide.  All I needed to do was to make the other dimension 5/64”.  I didn’t want to mill away ~70% of the bar so used a slitting saw to slice it to width.  This went pretty well.


As you can see, the internal stresses of the bar resulted in some warpage, but the part’s going to be bent anyway, so I wasn’t too worried about that.  But I did find it interesting that the skinny piece (the part I wanted) curved less than the fat piece.   I just found that curious.  I’d have thought just the opposite would happen.  But there you go.


Next, I drilled some holes – the outside holes will hold the bell pivot.  The center hole will be for the bell mount (to be made later).


I then used my high-tech radius jig on the belt sander to shape the sides of the stand.  First I made the fish belly in the middle.   (This shot was taken after the fact since clearly the next step has already been done!)


Then I put the radius on each end.


Now, just who’s bright idea was it to attempt to bend the part to shape without annealing it first?  I don’t know, but when I find that guy, he’s going to get a stern talking to!  What an idiot!  :cussing:


Back to the drawing board…  I considered NOT drilling the holes till after bending the part but the holes are SO useful in sanding it to shape, so I did it that way again.  And I’ll just be more super careful when it comes time to bend it to shape. And of course, I’ll make sure that idiot anneals the part before bending this time!   :facepalm2:


That will be first up on the agenda next time…

Thanks for looking in,
Kim

 

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