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Pennsylvania A3 Switcher

Build Log

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Mark Elen 107/12/2020 21:22:00
137 forum posts
343 photos

Hi All,

I have finally decided to make a start on this long term project. Built from the book by Kozo Hiraoka, it is a 3.5" gauge tender 0-4-0 loco. Kozo's book is excellent, aimed at the beginner (me).

There is lots of silver soldering before getting to the boiler, that's going to help me, as apart from a little bit of practice, I have never done any before.

I had been umming and ahhing over this or a 5" gauge Pansy, but I decided on this as I don't forsee it getting much running, and at this scale, it will be easier to move around and maybe put on display in the house?

So, having made the decision to start, I needed to make some tooling. Starting with some small boring bars, I bought the kit from Hemingway and got those made up. Here is the 1/4" bar with a 3/32 cutter bit


(I had to alter the holders to fit my quick change holder - the cast part is upside down to the drawings)

I also made up the 'vice bending tool' Kozo describes in his book. Here it is sat on the vice the wrong way:


The other thing I'm soon going to need soon is some way of winding the lathe by hand to make the springs Kozo describes. Apart from being fed up of using the chuck key to hold the chuck when tapping, I have been meaning to make one of these for a while.

I copied the design from Steve Jordan on Youtube here: Link





I made it so that it fits without opening the change gear cover, and being quick release, I'm hoping there is less chance of me leaving it in and starting the lathe.

More to follow.



Simon Birt08/12/2020 10:20:51
9 forum posts
5 photos

Good start, very laudable to make the tooling first, most of us dive in and then realise we don’t have the tooling needed.

IanT08/12/2020 11:06:48
1940 forum posts
194 photos

Kozo's books are a wonderful blend of Engineering and Art Mark - I have all of them.

Whilst in practice I will never actually build any of his engines, I have learned a great deal from studying his methods. I'm sure you will find working through his very clear instructions enjoyable and rewarding. I like your tools and your "attitude" (in making them first) is very 'Kozo' - I'm sure he would approve.



PS For anyone interested in Kozo's books - second-hand versions often appear at silly prices but the books are still in print.

Kozo A3 Pennsy


Weary08/12/2020 11:13:21
349 forum posts

Promises to be a very interesting build.

What do you intend to do for wheels? Are you going to buy castings? Or ....??



John Alexander Stewart08/12/2020 11:49:06
819 forum posts
56 photos


That's a good choice, in my opinion. His designs and instructions are second to none, and at the end you'll have a great little locomotive.

I built the 1st Shay, and am finishing up a Martin Evans "Ivatt", and have built a little LBSC locomotive. Kozo's design, (completeness and accuracy and instructions) leave the others in the dust.



IanT08/12/2020 15:00:50
1940 forum posts
194 photos

Lovely work JAS - Congratulations!

Phil - Kozo designs don't use any castings at all - everything is machined from the solid or fabricated - including the wheels. He even describes how to make a pressure gauge if you are so inclined....

Unlike the Pennsy, most of his designs are for N/G logging engines (by Shay, Climax & Heisler). For these, he describes how to modify commercial gears but does also show how to machine your own skew gears if you want a more prototypical gearing arrangement on your engine.

As John says his books really are in a class of their own - with everything there - (fold out) dimensioned drawings, isometric illustrations, inventory lists and very detailed step-by-step build instructions.




Edited By IanT on 08/12/2020 15:06:32

Mark Elen 108/12/2020 19:39:17
137 forum posts
343 photos

Hi Gents,

Many thanks for your kind comments.

Simon - I have been itching to get started, but I knew if I did, I would rush the tooling builds, just to make them, so I took my time with them and am fairly happy how they turned out.

Ian - Once I had the Pennsy book, I knew I would have to get them all. As you say, they are works of art in themselves. I'm still short of the New Shay and the Heisler, but am hoping to complete the set soon. My last purchase was the Climax and I really want to have a go at the Skew Bevel Gears - They will have to wait though.

I got my copies from Camden Miniatures in the UK.

Phil - It looks like the Pennsy is the only one in Kozo's series that has cast wheels. The book shows the making of a pattern to take to a foundry to have the wheels cast - the other books show ways of fabricating the wheels. I'm still unsure which way to go with this, Friends Models in the US sell a set of cast wheels. As I'm a long way away from getting to them yet, it will give me time to decide what to do regarding these. (Kim over on Model Engine Maker is building the Switcher and has a great build thread going, I believe he is going to fabricate his wheels, so I'm watching out to see how he gets on before I really decide.)

John - That Shay looks lovely. Beautiful.

Here are a few photos of where I am up to:

My Hacksaw got a bit of work over the last few weeks. As part of the hacksaw build is to remove the fan from the motor, I cut the discs from 2.5" EN1A Leaded bar in about 8 separate sessions per disc - 10 minutes running, then an hour to let the motor cool down. It didn't get really hot, but I didn't want to risk it


I gave each a quick skim cut on the lathe then set about grinding up the tool Kozo describes:


And with that, work commences:




I have gone a little 'off piste' from Kozo's instructions, as my discs didn't cut exactly square, so the plan is to dial in the bore that has been reamed 5/16 in the 4 jaw to dish out the other side. The first one took ages, now I'm getting the hang of it, the last one took about 15 minutes to face, dish, drill, bore and ream.



Mark Elen 113/12/2020 15:42:33
137 forum posts
343 photos

I got a bit more done this week on the Switcher.

All of the backs of the wheels dished out. I did the first side by scribing a circle with a set of dividers onto the blued surface, then taking the cross-slide to the line. They all ended up slightly different sizes.


So for the outsides, that will be more noticeable, I came up with a different approach. I noted down the cross-slide measurements at 0, 1mm, 2mm, 3mm and 3.17 then made up a sheet with each cut and where the cross-slide should end up:


I made up a little pin to fit inside the axle hole with a small centre spot drilled so that I could mark up the outsides as a 'sanity check' for the outside dish machining:



They are all now similar on the outside.


Once I got them all finished to this stage, I made up the mandrel and spent a long time getting it to dimension to hold the wheels for the next machining operations:


I'm now busy taking them down to finished dimension on the outside, then I can cut the tread and the angles.

There is a lot of work in these little wheels.

I'm having problems with my lathe at the moment. It turns on and the fan runs, but its hit and miss if the speed display turns on and without it, the lathe won't run. I was hoping it would be an easy fix, but it doesn't look like it. Anybody else had a similar fault with an SC4?



Mark Elen 115/12/2020 20:59:28
137 forum posts
343 photos

I'm still working away at the wheels. Not much left now.

One of the tools that I made before I started but forgot to post up was Kozo's centre indicator tool:


It is very good. It is quite easy to centre a a centre punched piece in the lathe.



Mark Elen 121/12/2020 20:54:36
137 forum posts
343 photos

I got a bit more done this week.

I finished off cutting the 3 degree treads and 10 degree angles on the flanges and got them all rounded off:



I then masked up the treads as best I could and got them sprayed up:



I wasn't too worried about overspray on the treads, as it will get sanded off when I finish the wheels. Whilst the paint was going off, I got on and made up the axles:


Here are the wheels before sanding:


That's as far as I have got.



Mark Elen 123/12/2020 18:54:10
137 forum posts
343 photos

The last couple of days I have been sanding the wheels as per Kozo's instructions. As I already have a couple of hand sanding bars that I made up ages ago per Chris's instructions on Clickspring Here I used them, instead of making up another and I didn't like the idea of sanding the tread and flange by hand.




Today, the length of track that I ordered, arrived from PNP and I spent a good hour putting it together, just in time to try these out:


They have all had a coat of Metalguard Ultra, that leaded EN1a wants to rust by just looking at it.

Now they just need to be loctited to the axles and that is the first chapter completed. On to the tender truck frames and journal boxes next.

Before I started loctiting the axles to the wheels, I chucked up a piece of Phosphor Bronze, drilled and reamed 1/4" and made sure that each of the ends of the axles will fit to save having to mess about later with the fits.



IanT23/12/2020 21:45:32
1940 forum posts
194 photos

Looking good Mark.



Mark Elen 129/12/2020 17:35:18
137 forum posts
343 photos

Hi Ian,

Many thanks for your kind comments.

I have been busy this week a bit at a time, getting the Journal Boxes and the Bearings made up. First job though was to sort out the Lathe:


It got to the point where it wouldn't turn on at all, or if it did, the speed was all over the place, like it had a mind of its own. A couple of weeks ago, I bought a new control board from Arc with the intention of changing it out when it needed it.

Unfortunately, because I had the old style board, I needed to change out the emergency stop and the front panel as well. I bought the whole lot from Arc as a bundle and this week, got the whole lot changed over and it has been no problem since. Result.

With the lathe sorted, I got on and got the Journal boxes to dimensions in the 4 Jaw, then drilled and bored out for the bearings. I made up a go/no go plug gauge at 10.01mm go and 10.06mm no go and got them all done. I only had to throw away 1 where I overshot the 10.06


I also got on and made up the barrel shaped bearings:



I then got the Journal Boxes set up in the mill, 2 at a time and milled out the groove for the arch bars:


Using the DRO, I got the first pair done, for a nice sliding fit on my gauge blocks set at 7.92mm (.312) then got all of them done, on both sides, the same.


Next up is 32 holes to drill and tap in these - it may take some time. I have decided to substitute the fixings Kozo calls out for these (3-48) with 7BA.



Mark Elen 101/01/2021 16:23:16
137 forum posts
343 photos

I got a bit more done over the last few days. All of the holes drilled and tapped in the Journal boxes - it didn't take as long as I thought it would, once I got going and into a rhythm with them. I then made up a couple of jigs to mill off the angles:









I'm now in the process of making up the bending/drilling jigs for the arch bars.



Mark Elen 109/01/2021 16:24:00
137 forum posts
343 photos

Bit more done this week. I got the Jigs made up, cut up the material for the arch bars and got it brought to dimension then started making up the arch bars. This went amazingly well. Only 1 reject bar that I bent in the wrong place.











The other thing I did was to make up the pieces for the columns. I also had my first go at silver soldering. It didn't quite go to plan to start with. I think I either didn't get the parts clean enough, or I didn't get them hot enough, as the solder ran, but didn't join the parts together at first go.

I did them a second time, pickling them first, then re-read Kozo's instructions and second time went a lot better






I'm pretty happy with them. Kozo's instructions are spot on. They all fitted together beautifully.



A Smith09/01/2021 16:51:01
59 forum posts
4 photos


Watching with interest, looking very good. Please keep posting.


br09/01/2021 16:59:25
807 forum posts
12 photos

Looking good, well done, and nice to see pictures of models being posted.


Phil H110/01/2021 17:39:10
424 forum posts
46 photos

Really nice work. I agree with Herr Dr. It is really nice to see somebody making something inbetween the posts on which lathe or mill we should buy..

Mark Elen 111/01/2021 19:51:22
137 forum posts
343 photos

Hi all,

Many thanks for your kind comments, I was a little concerned that nobody would be interested.

I spent today making up the tooling and getting the springs wound and the ends ground down. Kozo's instructions are spot on - the springs are shown in the drawings as .240" OD - in my language 6.09mm, mine turned out at 6.05 - thinking about it, when I bought the spring wire for this (and for all of the other springs) I couldn't find any .039" only .038" - there is the missing .04mm




Having made up the winding handle at the start of this project, it got a lot of use today.

Here is the result of the winding session before grinding the faces- I actually made 10 that were good, the top 4 were either too long, or too short


I then drilled out a piece of spare steel bar and set it up on my bench sander to grind the faces. The grinding took a long time this afternoon, as I didn't want to get the ends too hot or overshoot the dimensions.


And here are the best 8 ready to use


All in all a good day.



Mark Elen 118/01/2021 19:16:56
137 forum posts
343 photos

I have been busy this week making up the bolsters. They took longer than I expected due to the 3 degree angles on the sliding surfaces. I set up and milled the slots down to the maximum dimension, then set up again with the sine vice to mill off the angles.

Kozo gives some pretty tight tolerances for these. On the first lower bolster, I overshot the fore-aft dimension of the slot by .06mm, all of the others are on the tight side of tolerance. I'm umming and ahhing as to making up another lower bolster.








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