Pennsylvania A3 Switcher (Kozo)

[RReid]

Why not soft solder a shim on? Make it over size and file it to match after.

Hi kim. I think soft solder would be my approach as well. But it's your choice and I would expect JBW to work fine too. Anyway, it's looking really good! Just a small hurdle to clear.

[Kim]

PJ and Ron,
Yes, soft solder could be a good solution, but I'm planning to power coat the thing.  And the powder coating process requires that you bring the parts up to 450^oF for some time.  That is higher than the melting point of soft solder, so would fall apart during the baking process.

The TIX solder looks very interesting too, but with a lower melting point than standard soft solder, I think it will have the same problem with the coating oven.

So for now, I'm leaving it at JB Weld.  If that doesn't work, it will probably just be left as a shim.  And as Kerrin and Cnr pointed out, shims were very prototypical 

Thank you for following along.  I really do appreciate the input!
Kim

[RReid]

My bad. Been catching up a little and commented without reading all the back posts.

[Craig DeShong]

Kim

I'll admit that I check this thread only occasionally, but I recognize the tremendous amount of effort involved in building a live stream locomotive, having built an Allen ten-wheeler some 20 years ago.  Mine was a three and one half year project, even working on it nearly daily.

It looks to me that you have this project well in hand and I like what I see. 

From the sidelines... 

[Kim]

Thanks Craig!

Wow!  THAT is a big project!  My engine is tiny by comparison.  You should share a picture of it with us!  I'd love to see it.

Thanks for looking in Craig,
Kim

[Kim]

As we’ve been talking about, I used JB Weld to attach the shim to the yoke guide bracket:  (that’s a little piece of wax paper that I used to help the clamp not get glued in place.)


Then I filed the shim down to match the bracket.


Unfortunately, when I went to drill the hole in the shim, it popped off .  I had let it set for 12+ hours, but not a full 24, so maybe that had something to do with it.  But I think the main issue is that there’s so little surface area for the bond to hold.  I did try and rough it up some by scratching a waffle pattern into it and the bracket where it is being glued.  Ah well.

I mixed a little more JB Weld and reattached the shim, using the screw to hold it in place this time.  Hopefully, it will hold through the powder coating process.  If not, such is life.

I took this opportunity to disassemble things further and finally drill & tap the jackscrew holes in the heads and the steam chest covers.  Here’s a shot of one set (I already had the other set assembled when I thought of the picture!)  You can see the threaded jack screw hole at the bottom of each part.


When reassembling things this time I added some graphite yarn to the pistons and put the o-rings in place on the piston rod.  I’d also never had the O-ring retainers in place, so that took some fitting and adjustments.


Chapter 17.1 – Valves

With things reassembled and running smoothly, I then moved forward to the valve gear.  There’s a lot of valve gear in this engine!  But the first element is the stem valve itself.

Kozo specifies bronze for this part (I’m using 932 bearing bronze).  I started from 5/8” nominal round bar.  This stuff is cast oversized so I ended up having to use a 43/64” collet to hold it.

First I shaved about a 3/4" length to 3/8” x 1/2".


On one of the 1/2" wide sides, I started the pocket for the steam valve with a 1/4" 2 flute end mill.


Switching to a 1/8” end mill I widened the pocket to the specified size.


Then, flipping the whole thing over, I cut the slots in the top of the valve for the valve nut and the valve rod using a 1/16” end mill.  Note that the long slot is NOT centered.


Then I cut the part off from the parent stock.   I need to do one more of these, but this is where I stopped for the day.


And just for fun, here’s the bottom side showing the steam pocket.  The left side still has to be milled square and to length.  When that’s done, the pocket will be centered on the valve.


Kim

[kvom]

As to that shim, you could pre drill a hole larger than the screw.  But it seems to me that the JB will make it thicker and require some filing after powdercoat.   Why not just coat it separately on the edges only and leave clamped in the assembly?

You could also use loctite, which would be a thinner adhesive.  I used it to glue some repair blocks on the cylinder of my Greene engine, and it survived powdercoating.

[Kim]

Interesting.  So was that just standard red Loctite?  Or some high-temp version?

At this point, if it falls off during powder coating, it will likely end up as say here, just clamped in place by the screw holding the guide.  And the edges will be coated.  Or I might Loctite it after coating if it falls off.  We'll see. That's a ways away still!

Thanks Kvom,
Kim 

[Craig DeShong]

Thanks Craig!

Wow!  THAT is a big project!  My engine is tiny by comparison.  You should share a picture of it with us!  I'd love to see it.

Thanks for looking in Craig,
Kim

I will be the first to state that, having built one, building a live steam locomotive is a monstrous project.  Many are started, few ever get finished.  I have a friend who has been building one for 35 years; I doubt he will ever finish it.  I don't mean to belittle his efforts, it's just that the commitment is daunting.

I'll give you a photo of my locomotive, fronting it's consist below:

[Kim]

Wow!  That's a magnificent locomotive!  Thanks for sharing the picture   

You should feel good about that!  That's one impressive project, and you completed it!

Thanks Craig!
Kim

[Kim]

Continuing on with the valves:

I completed the 2nd valve up to the same point and sawed it from the parent stock.

Then I trimmed the sawed end to the final length:


All that’s left is to make the fancy angles on the sides of the valve.

First I cut the shallow angle – this one worked out to be a 13^o angle.  So I set it up with some angle blocks and shaved off a little from the skinny side.


Next I did the 45^o bevel on the other side.


And finally, the same (45) on the other two ends.


Unfortunately, when doing the second valve, I got a little cocky and took too aggressive of a cut.  This valve is so thin with the pocket on the underside and the deep grooves on the front side.  But everything had been going so well.  Guess I found the limits of 1/64” of bronze! 


Another shot of my bungle out of the vise.


I knew better.  I was being really careful.  But as I said, it was all going so well, and I guess I let myself get in a bit of a rush to get it completed.  Live and re-re-re-learn...

So, time for me to call it quits for the day.  I’ve got one valve complete at least.  I’ll redo the other one next time.

Thanks for looking in,
Kim

[Don1966]

Man what a bummer. Well as the saying goes you’re still learning and believe me you will never stop learning the hard way. They just get farther apart…
You got this Kim…..

Don..

[90LX_Notch]

That’s a bummer Kim.

-Bob

[crueby]

Ouch!  At least you get the fun of making another part.      we've all been there.

[RReid]

Clean up the edges, buff it up, hang it from a gold chain, and give it to someone as "art jewelry".