Author Topic: Pennsylvania A3 Switcher (Kozo)  (Read 464579 times)

Offline Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #4095 on: June 05, 2024, 05:42:52 AM »
Fiddly Fittings Fest 2024!  I love alteration  :Lol:

Kim

Offline Minh Thanh

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #4096 on: June 05, 2024, 11:52:00 AM »
 :ThumbsUp: :ThumbsUp: :ThumbsUp: !!

Offline Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #4097 on: June 06, 2024, 10:38:15 PM »
Thanks, Minh!  :cheers:

Kim

Offline Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #4098 on: June 06, 2024, 10:49:14 PM »
The main valve body was made from 5/16” hex brass.  The end was turned to 19/64” diameter.  To make the ball shape in the middle, I used my round-nosed tool to mark the ends:


Then rounded the middle with a file.  Looks like I should have had a smaller radius tool, or maybe not gone quite as deep.  Ah well, it will do its job and I think it will look fine in the end.  Then I parted it off.


Next, I flipped it around in a 19/64” collet and turned the opposite end to 1/4" diameter, and used a die to cut 1/4"-32 threads. Then  I put a smallish hole all the way through the part and a slightly larger shallow hole in the end that will nest with an incoming pipe nipple.


I need to make the holes where the vent valve and the boiler nipple will be soldered in.  These holes are located 90o from each other.  Interestingly, the two check valves are not identical – they are left and right handed, so one has to have the holes 90o in the opposite direction from the other.  I marked the spots for the holes with a Sharpie, to help keep me from making a mistake here.  I held the part by the threaded end using a 1/4" collet to make a flat with a 5/32” end mill:


Then I spotted and drilled a 1/8” hole for the attachment to fit into.


Luck was going my way today and I got the holes in the right places! Yay!  Here are all the parts that will be joined together to make the check valves.


And here they are loosely fitted together to give an idea of what they should look like.


The next step will be soldering.
Kim

Offline cnr6400

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #4099 on: June 07, 2024, 03:11:28 AM »
 :ThumbsUp: :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :popcorn: Top notch work Kim!
"I've cut that stock three times, and it's still too short!"

Offline Zephyrin

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #4100 on: June 07, 2024, 09:56:51 AM »
lot of tiny parts, I'm always nervous of soldering such small parts without everything being fixed in one block !

Offline Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #4101 on: June 07, 2024, 05:39:18 PM »
Thanks Jeff and Zephyrin!  :cheers:

lot of tiny parts, I'm always nervous of soldering such small parts without everything being fixed in one block !
Yeah, that's the trick, isn't it?  :embarrassed:

Hopefully, I'll be able to do it.  Some of that correction fluid in the right places could help out.  We'll see! 

Kim

Offline crueby

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #4102 on: June 07, 2024, 05:45:40 PM »
Also if can suspend it from the compression nuts, it will keep solder and flux from running down to them.

Offline Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #4103 on: June 07, 2024, 05:49:07 PM »
Also if can suspend it from the compression nuts, it will keep solder and flux from running down to them.

Good point, Chris!

Kim

Offline Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #4104 on: June 07, 2024, 10:49:58 PM »
Well, today was one step forward, two steps back day.  Never the funest of days.

Thins started off wonderfully with a nice session at the solder station.   Here’s one of the check valves with the parts in place, fluxed, with solder, ready for heating.  I used a 5/16” – 24 plug in the top of the union nut to hold it in place out of the way where it wouldn’t get soldered.  I was going to make a quick threaded part to do this but it turns out I already had one in my collection of brass plugs.  How fun is that?  My theory is, with the part in this position, gravity should help keep the solder where I want it.


After soldering, a pickle, and some cleanup with a little wire brush in the Dremel, they looked pretty good!


The next step was going to be to make the ball seat for the check valve.  In preparing for this, I noticed there was crud in the inside passageways.  So I got the appropriate sized drill bits to clean them out.  It was at this point that I realized my mistake (the two steps back part).  I’d made the vent valve seat incorrectly.   I had misread the drawings and made the through hole #47.  It was supposed to be #56 (a pretty big difference!).  That #56 hole was supposed to make the seat for the vent valve.  If I’d only been off a little bit, I’d probably just said ‘oh well’ and gone on.  But #47 is almost as big as the 4-40 threads used for the vent valve.  I’m sure what happened is I saw the .047” there and grabbed the #47 drill.  But with the valve seat that large I wasn't sure that the pointy part of the valve stem would seal it properly. Maybe it would, but likely it wouldn't.  Stupid mistake :(


What to do?  After a session of kicking myself and smacking myself in the forehead, I finally came up with a plan.  I’d try and remove the misdrilled vavle stem seats and make new ones with the correct hole size and solder them in.  But how to evil ones?  This is what I came up with.  I threaded a 4-40 screw into the valve seat then clamped a vice grip onto that screw.  The vice grips would act as a weight, and if I heat the up assembly with the vice grips dangling over a precipice, then gravity should help pull the incorrectly made valve seat out. Right?  Right!


With the incorrect vent valve parts removed, I went back to the mill setup to clean up the mating faces.  I used a gauge pin (and other means) to make sure things were oriented properly, then did the end mill, drill routine again so the part was ready to receive the new, correctly drilled, vent valve seat.


Here are the parts as they stand now.


Next shop time I’ll create new, hopefully correct, vent valve seats and solder them in place.

Then I’ll be up to where I thought I was a few hours ago.

If you didn’t have setbacks like this, it wouldn’t be a fun hobby, right?  Nothing to overcome, nothing to give you that sense of accomplishment when you persevere, right?  I’m going to keep telling myself that anyway.

Kim

Offline crueby

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #4105 on: June 07, 2024, 11:01:35 PM »
Nice recovery from an easy-to-make mistake!  Think back to when you started this project - probably would have had to scrap the parts and start all over? The experience you've gained showed you how to recover from it.   :ThumbsUp:

Offline Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #4106 on: June 08, 2024, 02:15:42 AM »
Thanks, Chris, nice spin.  I appreciate it!  :embarassed:

Kim

Offline cnr6400

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #4107 on: June 08, 2024, 12:55:56 PM »
 :ThumbsUp: :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :popcorn: It's sometimes really difficult to un-silver solder parts. Many times parts are damaged while pulling on them (whether with vise grips or bulldozers). Course it never happens to me.  :embarassed: (well not more than a few times a year anyway)  :Lol: 

Glad you were able to save the valve bodies. Let Fittings Fest 2024 continue!  :cheers:
« Last Edit: June 08, 2024, 08:26:33 PM by cnr6400 »
"I've cut that stock three times, and it's still too short!"

Offline Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #4108 on: June 09, 2024, 05:08:11 PM »
Thanks Jeff!  :cheers:

Kim

Offline Buggs

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #4109 on: June 10, 2024, 04:02:51 PM »
Hi gals & guys,

This is my first post, so please excuse me if this is the wrong place to ask this question.

I am very interested in building the A3 Switcher using Kozo’s book and of course the excellent information on Model Engine Maker and this post. I’m in the process of collecting information for this wonderful adventure. Unfortunately, I have immediately hit a major roadblock, I can’t find a copy of Kozo’s book, The Pennsylvania A3 Switcher.

Do any of you fine folk know where to source a copy, new or used.

Thank you for any suggestions or leads,
Tim

 

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