Author Topic: Pennsylvania A3 Switcher (Kozo)  (Read 144348 times)

Offline Don1966

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1680 on: May 25, 2022, 05:08:57 PM »
Awesome Kim your craftsmanship is top notch buddy.   :Love:




 :cheers:
Don

Online pmerritt

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1681 on: June 09, 2022, 05:48:07 AM »
Wonderful work Kim! I have really enjoyed this build log. Thank you for all the extra effort you put in so we can all enjoy the ride!!


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Offline MJM460

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1682 on: June 09, 2022, 09:46:31 AM »
Definitely no need to be embarrassed, Kim.  You are doing amazing work.  It’s a big project and taking a break for whatever reason is almost certainly a positive in some ways.

When you come back to it, we will all be here ready to continue following along.

In the mean time, I’m enjoying your side project.

MJM460



The more I learn, the more I find that I still have to learn!

Online Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1683 on: June 09, 2022, 04:55:24 PM »
Thanks, Pmerrit!

Thank you MJM!
Yes, I',m having a grand time with my new side project.  It's kind of reinvigorating to be working on something different for a bit!  But I'm also looking forward to getting back to the Pennsy, too!

Kim

Offline samc88

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1684 on: July 06, 2022, 02:11:27 PM »
This is looking excellent Kim, Im looking forward to getting back on my own project once my lathe is back in action

Online Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1685 on: July 06, 2022, 05:12:16 PM »
Thank's Sam!

I'm back on this project now, but starting out slow.  It's amazing how much time I spend thinking about a part and planning my sequence of operations for these tiny parts.  With the belt grinder I just churned out parts much more quickly.  But the tolerances were a lot less stringent.  But it's all fun!

Kim

Online Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1686 on: July 10, 2022, 10:25:47 PM »
This week I started back on the Pennsy, with the next major subassembly being the Cylinder Cocks.  They sound so easy, but there's quite a bit of mechanism to these since they have linkages that allow you to open and close the cocks from the cab.

Chapter 19.1 – Cock Bodies

The first part of the Cylinder Cock assembly is the cock bodies themselves.  They are made out of bronze. I used 932 bearing bronze, which machines really nicely.

The smallest bronze I purchased was 3/8” nominal – which is really more like 0.412” I had to use a 27/64” collet to hold it. So first I turned it down to the specified 0.200” for the main cock body, then turned down the last 1/8” for 8-36 threads.


Then I drilled the main drain hole. This had to be deep enough to get close to the bottom of the drain cock, but not break through.  I had to trust my math on this one.   :o


The last step on the lathe was to narrow down the ‘bottom’ part of the cylinder cock and make a little taper, then cut it off from the parent stock.


I made four of these.  The picture on the left shows where we’re headed.  Still have two holes to drill crossways. The big one goes all the way through and is where the actual on/off valve will go.  The lower smaller hole only goes in halfway to connect to the central drain hole.


To get these cross holes in the correct position, I fitted all four of the cock bodies in place on the cylinders.  It was hard to get these in tight since there was nothing to grip on, and I didn’t want to use anything that would mar them.  With them in position, I tagged them with a 1/16” number punch so that I could get them all back in the same spot.  To mark the location for the holes, I colored an area with a black permanent marker, then used a small flat file to gently rub along the front leaving a very small mark at the correct location.



To drill these holes I followed Kozo’s directions and made a little jig to hold the cylinder cock bodies. There’s a ~0.200” hole in the side where you slide the cock body into, two holes on top for the locations of the two cross holes, and a set screw on the side to hold the cock in place. My additions to this little jig were to use a small spring behind the cock body so it would push out against my stop that I would position exactly 1/8” from the side of the jig. This made positioning the cock body much easier!


Here’s what the jig looks like in use.  You can’t see the spring, but it’s in there behind the cock.  The two 1/8” chunks of aluminum being held by the clamp are used to set the position of the top of the cock.  I used tweezers to rotate the cock till I could see the witness mark and would adjust that till it was as close to centered on the holes as I could get it, then tighten down the set screw.


And now, drill the two holes. For the larger hole (the one I’m drilling in this picture) Kozo specifies to ream it to 0.100”.  My problem with that is it’s hard to come by 0.100” rod in the states.  I chose to make it 0.0938” (3/32”) which is readily available, and pretty close to 0.100”.  So I drilled the holes with a #43 drill.  The other hole was drilled with #56 with the depth CAREFULLY controlled since it only needed to go halfway through to meet the other central hole in the cock body.


After I did that for all the cocks, I went back through, lined them each up again, and reamed the large hole to 3/32”.


And here’s how the cock bodies look now:


The next part up is the cock plugs that go through the cock bodies and actually open and close the cocks.

Thanks for looking in on me!
Kim

Offline crueby

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1687 on: July 10, 2022, 10:30:42 PM »
Nice!    :popcorn: :popcorn: :popcorn:

Offline cnr6400

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1688 on: July 10, 2022, 11:01:10 PM »
Those look great Kim!  :ThumbsUp: :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :popcorn:

Online Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1689 on: July 10, 2022, 11:09:32 PM »
Thanks Chris and CNR,
Getting a roaring start here, eh?  :Lol:
Kim

PS We need a snail emoji!  I could use that :)

Offline RReid

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1690 on: July 10, 2022, 11:52:23 PM »
Nice work Kim. That's a clever idea to add a spring to the drilling jig. :ThumbsUp:
Regards,
Ron

Offline Admiral_dk

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1691 on: July 11, 2022, 11:12:06 AM »
Great to see you back on the Pennsy Kim  :ThumbsUp:

Love your descibtions - very informative  :cheers:

Per

Offline joe d

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1692 on: July 11, 2022, 12:44:01 PM »
Great to see you back on the loco Kim. (but I certainly did enjoy your side trip with the belt grinder!)

Clever idea with the spring.

Cheers, Joe

Offline propforward

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1693 on: July 11, 2022, 01:45:32 PM »
Top work as always - love the fixturing approach for the production run of components!
Stuart

Forging ahead regardless.

Online Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1694 on: July 11, 2022, 04:10:03 PM »
Thank you Ron, Per, Joe, and Stuart!  :cheers:

Today is family celebration day at our house (daughter's birthday), so no shop time ...  maybe later in the week?

Kim