Pennsylvania A3 Switcher (Kozo)

[Admiral_dk]

Great to see them in place Kim 

Per           

[AdeV]

And are the slotted clamp screws going to be swapped with stud and nuts?

No plans to.  This is what Kozo shows for the clamp screws.  I don't know how prototypical it is though...

It's hard to be certain from this picture, since it's so small, but it looks like the smokebox door is not, in fact, round - but has protrusions through which the clamping bolts are, presumably bolted.



On the other hand, this slightly less small photo (which is the same engine, but later & maybe after a refit) seems to have a round door, but still "bolted through" rather than clamped:



Source: https://arrts-arrchives.com/sthosp3.html

[ddmckee54]

I'm thinking that maybe the poor engine had a boo-boo between the first and the second pictures.  In the first picture the end of the smokebox appears to be a one piece casting, or maybe a forging?

Judging from the rivets in the second picture, the end of the smokebox seems to be fabricated from several pieces.  Maybe somebody got a little too close to something big and hard? 

[Kim]

Nice pictures, Ade!  I hadn't seen those before.

I did a little more internet looking and came up with this one (again, not very high-res):


And if you zoom in on the smokebox door (even WORSE resolution) it looks like these are clamps holding the door closed and they MIGHT be being retained with studs & nuts.  Hard to tell, but the closest clamp, just above the center, certainly looks like a stud.


Another thing I noticed is that the handrail on the smokebox is around the lower part of the door rather than the upper part as Kozo puts it.  This makes sense as the place where you're walking and would need a handrail is along the bottom there, not around the top.  Hmm...

Well, I'm certainly not going to change it!  I'm happy to follow along with the plans in Kozo's book.

Interesting information though!

Kim

[Admiral_dk]

The low number has the Rail up High and the High number has the Rail down Low ....

Maybe it startet out up High and experience showed that it was much more needed down Low - like you say Kim - to avoid burns and to Hold on to 

Per       

[internal_fire]

Number 317 is an A5. Number 3 is an A3.

Gene

[glinscott]

I wanted to say thank you for the amazing build log, and congratulations on your build so far - it really looks incredible.  Really appreciate you putting together a clear BOM as well, that's also been a huge help (although I've only purchased the wheels so far - that was already confusing enough for a beginner .

This thread will almost certainly serve as the definitive reference on building the A3 - really appreciate you including all the troubleshooting details and how you made your decisions as well.  Looking forward to reading each new section as I get there in the book!

[Kim]

Thanks Per! 

Number 317 is an A5. Number 3 is an A3.

Gene

Thanks Gene!

Guess you can't believe everything Google tells you, eh?  I should have realized that was why I hadn't see this one before in my A3 searches. I'll have to check on the real A3 photos I've seen...

Kim

[Kim]

I wanted to say thank you for the amazing build log, and congratulations on your build so far - it really looks incredible.  Really appreciate you putting together a clear BOM as well, that's also been a huge help (although I've only purchased the wheels so far - that was already confusing enough for a beginner .

This thread will almost certainly serve as the definitive reference on building the A3 - really appreciate you including all the troubleshooting details and how you made your decisions as well.  Looking forward to reading each new section as I get there in the book!

Thank you for the kind words!  I've learned so much doing this build and received so much help from everyone on this forum.    I can be fairly confident that any valuable information you learn from my build log was provided by the generous here on MEM!

And I hope you find the BOM of value.  I have updated it a couple of times and need to do another update for the mistakes I've found in the smoke box section of the BOM.  Just a few, but I will continue to update it over time.  So check back from time to time

Kim

[JRP52]

I've been checking the BOM for updates - they do come in handy!

[Kim]

Chapter 25.8 – Stack

The next item on the smokebox is the smoke stack!  We’re getting to some pretty defining things in a locomotive!

The stack is made in three pieces – one piece will be the base or the saddle. The next piece will be the smoke stack proper, and the third piece is a collar that fits on the stack inside of the smokebox to hold the stack in place.

I will be starting on the stack base today.  But one of the operations will require a 9/32” radius cove to be turned on the part.  I originally thought I could use a 9/16” ball end mill in a tool holder on the lathe to make this shape, but once I actually looked at the end mill, I realized the cutting edge was pointing the wrong direction for what I needed.  If I’d been forming the shape on the left side of the tool I’d have been in good shape. But the way I’m doing it, it has to be on the right side of the tool.  That’s just the wrong side of a right-handed end mill!  So, I decided to make a 9/16” button and hold it in my button holder that I used for making gear cutters a la Ivan Law.  I thought this was a pretty clever idea.

To make the 9/16” button I used 3/4" W-1 tool steel and formed the basic shape.  The 3/16” stud will be to fit in the hole on the button holder.  The bigger part is the 9/16” button, of course.


Here’s how it’s going to sit in the button tool holder.  Note that the way Ivan Law has you make the tool holder puts the button at a 7^o angle to provide clearance on the front side of the button, so I will need to cut the top flat when it’s held at that angle.


Here was my first attempt at cutting the button flat on top.  I used red Loctite to hold the button in place (which is what you do while using the button for turning).  I was taking very shallow passes which worked fine for the first few, but once it started biting in much, this is what happened!  The button spun in circles!  Made a neat pattern, but not what I really wanted.


This should have worked and probably would have, but I didn’t wait long enough for the Loctite to cure. When I pulled the button out, that was very clear.  Ah well. So I just did it using a collet block, which is what I probably should have done the first time around.


I heat-treated the button and tempered it.  Sorry, no pics of that.  I had to heat treat it twice because I got overly aggressive in my tempering.  But I think I finally got there. 

Since I only need half the tool to cut the profile, I left that step there at just past halfway. I thought it would be helpful in lining up the tool button on the holder.


Turns out it was very helpful! 😊


Also, since the 9/16” button is actually tilted by 7 degrees, it won’t describe a perfect quarter circle.  It will be slightly elliptical.  But it will be ever so slightly - only off by about 0.004".  I decided that it was close enough.  I’ll be doing a bunch of filing work around there anyway. This will just help get the shape close to start with.

With the Loctite curing on the button tool, I started work on the stack base.  I making the stack out of 303 stainless steel.  This is a 3” length of 1 5/8” diameter 303.  I turned it down to the specified outer diameter and started drilling the hole where the smoke stack will go.


I’m going to step drill it up as far as I can then start boring it out to the required ~7/8”.

But this is all the farther I got today.  The rest of the drilling and boring will have to take place next time.

Thanks for looking in!
Kim

[cnr6400]

 

[Kim]

Thanks Jeff! 

Kim

[Kim]

It’s been a few days since I made an update on my build.  That’s because, at the end of last week, I and everyone in my house came down with Covid-19.  We went 38 months without getting it, but there you go.  It’s like they say, there are two groups of people in this world, those who have had Covid, and those who are going to get it.  I’m now in the former camp.  Or at least, I’m recovering from it.  Still have aches and pains all over and food tastes weird (even water tastes bad, if you can believe it!), but I was feeling well enough to venture out into the shop today, after sitting around in the house for the past 4-5 days doing nothing (and feeling like doing even less!).  But there you have it.  Enough about that, eh?


I’d just finished up the button tool and turned down a chunk of stainless to start on the base for the stack.  I had just started to drill the center hole for boring.  But as I started today, I thought better of that.  I decided that my little button tool was going to require a lot of force to cut that large of a radius so maybe I should do that before I bore out the center.

So that’s what I did.  I stopped drilling and instead, used a grooving tool (modified parting blade) to approximate the shape for the 9/16” radius button.  I was originally going to remove half of the material so the button tool only had a quarter radius to cut.  But then I thought maybe I should take out a little more of the waste with the grooving tool to more closely approximate the shape of the radius, like so:


Then  I mounted up the 9/16” button tool and started to use that to form the quarter-round shape.  It was going quite well and I was very pleased until I got to where I had nearly full engagement of the button.  It was taking a LOT more tool pressure to start cutting.  Once it was cutting, it went ok, but it would stop cutting and I’d have to add extra pressure to get it to start cutting again.  I was worrying that maybe I’d caused some work hardening or something. And I should have stopped there. But no, I added just a little more pressure and it started cutting, then BLAM.  It bit in so hard it snapped the button right off the holder.


Hind site is 20-20, right?  Clearly, I should have listened to my uh-oh feelings and stopped pushing it. I will next time.  I promise!

Here’s a closeup of the tool.  You can see it snapped right at the base of the 3/16” stud that was holding the button in the tool.  (This is the back side of the button, not the cutting edge.)


I was pretty sure I could salvage this – the part, not the button tool

I used a round file to clean up the worst of it and it looks pretty OK as is.  There’s going to be a lot more file work on this part anyway, so you’ll never know what happened.  It’s just humbling to know how I goofed that up so admirably.  But then, any landing you can walk away from is a good one. One you can learn from, right? 

Here you can see where the tool really dug in on the left side.  I’m kind of thinking that my having uneven loading on the tool probably didn’t help this.  On the right side, there was a full quarter circle engaged with the work, and on the left side, just the lower bit was engaged.  I’m wondering if that’s one reason it dug in on the left side.  Or I was just stupid and didn’t listen to what it was telling me.  It just wasn’t sharp enough to do what I was asking it to do. (Mostly likely case.)


Here’s a picture showing the right side more. You can see there’s still a bit of a gouge there.  But I’ll position the part in the next operations so that this will disappear and no one will ever be the wiser!


Regardless of my little mishap there, I actually feel pretty good about that button tool.  It really did its job quite well.  I was just expecting a little bit too much from it for that last bit.  Next time I’d probably do a similar profile on both sides.  And maybe make my stairsteps a little closer together than I did here.  I was being pretty rough in my approximations.  I’d leftover 0.050” to cut at full tool engagement, and apparently, that was too much to ask.

With that excitement behind me, I then went back to step drilling out the center hole up to about 13/16”, then used a stubby boring bar to widen the hole to a few thou over 7/8”.  Then I made a step at 29/32”.  This step will be used for a retention device in our next setup.


And with all the boring done, I cut it off:


And there’s the current progress on the stack base.


Next, I’ll be making the fixture to hold it for cutting the radius on the bottom so it fits over the smokebox!

Thanks for joining me on my daily learning excursions.
Kim

[crueby]

Glad you are recovering, hope that continues well!

The base is looking great so far - lots of filing in your future when you get to blending the sides down onto the boiler. When I did my Shay I used brass for the stack to make the shaping easier, even so it was a lot of work with a coarse file then finer ones.