Author Topic: Discussions on Kozo’s A3 Pennsy Switcher  (Read 1153 times)

Online Kim

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Discussions on Kozo’s A3 Pennsy Switcher
« on: February 13, 2023, 05:09:09 AM »
The purpose of this thread is to provide a central repository to collect discussions of issues or difficulties with specific drawings or sections from Kozo Hiraoka's book "The A3 Pennsylvania Switcher."

Index:
Chapter 23
Figure 23-1   - Figure 23-1 vs Figure 23-11: Smokebox Mounting Stud dimension discrepancy
Figure 23-11 - Figure 23-1 vs Figure 23-11: Smokebox Mounting Stud dimension discrepancy

Chapter 28
Figure 28-8, Hole for link in the Trunnion is shown the incorrect size
Figure 28-12: Fork width in Link has the wrong dimension



Background Info:
A few days ago on another thread, Bob, me, and a few others were sharing some difficulties we have experienced interpreting some of Kozo's drawings.  Don't get me wrong here!  Kozo Hiraoka has done a masterful job with all of his books. The drawings are excellent and there are very few errors in them.  But, there are a few. And it can take a while to really determine if it's a mistake or if you're misinterpreting something.  So, after an off-thread exchange between Bob and I, we decided it could be helpful to others to collect these discussions in one central place - outside of any one specific build.

To make this easier to navigate, the plan is to maintain an index here in this first post, by page/drawing to allow people to see what drawings have been discussed already and jump to that section.  I will be maintaining the index as best I can, but feel free to point out if I've left something out.

At least, that's the plan.

I would ask that everyone feel free to contribute to this thread for its stated purpose: to discuss issues or difficulties with specific drawings or sections from Kozo's book "The Pennsylvania A3 Switcher," but to keep it focused on that and not drift off into people's specific builds.  That should be covered in their build threads.

Hopefully, this will be a valuable resource for other people building this excellent model!
Thanks,
Kim
« Last Edit: October 31, 2023, 10:32:06 PM by Kim »

Online Kim

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Re: Discussions on Kozo’s A3 Pennsy Switcher
« Reply #1 on: February 13, 2023, 05:15:22 AM »
To kick this off, I'll add one of the issues I found in the Boiler section (chapter 23).

Figure 23-1 vs Figure 23-11: Smokebox Mounting Stud dimension discrepancy

In figure 23-1 (upper side view of the boiler) it shows the mounting boss on the smokebox studs to be 1/4" dia.
But in figure 23-11 he shows to ream the hole for the smoke box stud to 7/32".
I'm sure either dimension would work, but you need to make sure they are the same.  I went with 7/32" because I'd already drilled and reamed the holes in the front tube sheet, but 1/4" would work fine too.

Kim

Offline internal_fire

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Re: Discussions on Kozo’s A3 Pennsy Switcher
« Reply #2 on: February 13, 2023, 02:14:45 PM »
There is an extensive discussion of various errors on another bulletin board.

https://livesteam.proboards.com/thread/164/mistakes-errata-changes

I  believe the board is mostly or completely inactive, but it is still accessible.

Gene

Online Kim

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Re: Discussions on Kozo’s A3 Pennsy Switcher
« Reply #3 on: October 31, 2023, 10:24:38 PM »

Figure 28-12: Fork width in Link has the wrong dimension

On page 168, Figure 28-12, the drawing of the Link, shows the narrower fork to be 0.785” wide.  For one thing, the part is only 1/4" wide to begin with.  But it’s clear this was supposed to be 0.0785” for the narrow fork since it is supposed to slide over the tab on the trunnion, which Kozo made 5/64” (.0781”) thick.  He probably meant 0.0785" for the fork width.

Kim

Online Kim

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Re: Discussions on Kozo’s A3 Pennsy Switcher
« Reply #4 on: October 31, 2023, 10:26:59 PM »
Figure 28-8, Hole for link in the Trunnion is shown the incorrect size

Page 168, Figure 28-8, the drawing of the Trunnion shows the hole on the larger tab to be 5/64”, which is 0.0781”.  But that hole will be receiving a #2-56 screw, and the major diameter of a #2 screw is 0.086”.  No way that’ll fit through the 5/64” hole.  Anyway, Kozo probably intended to show #44 (0.086”) for that hole which is what he uses for a #2 close fit thru hole.

Kim

 

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