Pennsylvania A3 Switcher (Kozo)

[Kim]

Today I did the final step on the eccentric strap of tapering the edges of the eccentric rod tabs to match the profile of the eccentric rod.

Then I mounted it between the eccentric and the pump lever then proceeded to make sure it worked.  Of course, it didn’t.  The lever moved, but if there was any pressure on the pump mechanism the ratchet wheel wouldn't advance.

I had done the math on this and it was clear that Kozo designed the eccentric throw (1/4”) and lever length to have just the right amount of travel to move exactly ONE click of the ratchet.  However, that means that you have to start the throw with the lever ratchet JUST past one of the teeth.  If you start the throw halfway before the tooth, then when you move the full throw you only have it halfway to the next tooth, and the upper pawl won’t engage the next tooth.  And this is exactly what was happening to me.

I'm sure there are multiple solutions for this, but what I did was to adjust the length of the spring pawl on the lever.  I made it the correct length to just pick up the tooth at the farthest extent of the throw.  This meant that as it went back the other way the maximum possible rotation (which isn’t much) would be imparted to the ratchet wheel, thus guaranteeing that the upper pawl would engage with the next tooth.

Luckily, I'd foreseen this problem and when I remade that spring pawl I left it a little long.  The new length was still longer than the 1/2" specified by Kozo.  Not by much, but enough to make a difference.  The teeth on that wheel are just about 1/16", so the lengths of those pawls are very critical!

Sorry for the clunky explanation, but the fix worked!

Here’s a shot of both pumps (feed water and lubrication) and eccentrics installed.  This is right side up, so the oil cups could actually be filled and the oil wouldn’t run out.  The back eccentric is for the feed water pump, and the front one is for the lubricator.  Note the lubricator cover is not in place in this photo so you can (kind of) see the internals of the pump.


And here’s a shot with the cover installed.


I also adjusted the eccentrics so that they were 180^o out of phase.  I figured this would spread the load of the pumps more evenly across the full rotation of the wheels.

Next up is the Grate and Ashpan!

Kim

[cnr6400]

 

Grate great to hear!

[Kim]

Grate great to hear!

[Admiral_dk]

Nice to see them both in-situ 

Per

[Kim]

Yes it is! Thanks Per!


Chapter 22.1 – Grate

Over the weekend and today I worked on the grate.  This is, of course, the grate for the coals in the firebox.

The main bars for the grate were cut from 1/8” x 1/2" 303 stainless steel bar.  I would have liked to use 3/8” instead, but all I could source was 1/2".  So I had to cut it down to width.

Here are the 8 bars, all sandwiched together, with 1/8” holes drilled in them.  I lined them up on 1/8” rod to keep them all uniform.  Here I was cutting them to width (3/8” as discussed above) and to length – some off of both ends to make the holes a specific distance from each end (7/8” to be exact).


Then I chamfered the ends of the bars.


Next, I moved to the lathe and cut a bunch of little 1/4" stainless steel donuts to use as spacers between the bars.  I drilled the 1/8” center hole in about 1” which gave me room to cutoff about 5 of the little donuts.  Then I’d slide the rod out a bit and do another chunk of them.


It took a while, but I got all of them cut.  I need 18 of them but did 20 as a tax to the shop gnomes.


Here I’ve lined up the full suite of bars and spacers to see what the final width will be.  It’s SUPPOSED to be 2 5/16” when I’m done.  You can see that this is about 47 thou over the goal.  I’ll trim it down to the required width pretty soon. But to assemble it all, I wanted to make sure I cut the 1/8” support rods long enough that they’d fit. 


So, after cutting two lengths of 1/8” 303 stainless steel rod to my 3.60” that I determined above, I drilled a small center hole in each end of the rods. (no pic – it didn’t look like much).

For the outer four spacer donuts, I chamfered the inside hole just a bit.


Now, to carefully assemble the bars and spacers:


After getting it all assembled I used a 60^o punch to flare out the 1/8” SS rods on the ends to lock everything in place.


And there you have it – the completed grate!


Remeasuring after all the pounding, the width is now ~2.330”  So I’m only about 18 thou over where I need to be (2 5/16" = 3.3125 for all of you metric people).  And that’s right on!  The outer spacer donuts are supposed to be just a tad thinner than all the inner spacers.  I just chose to make them all the same and to trim it up after the fact – after I’m ready to fit the grate between the brackets!

So I’m pretty pleased.  The grate has a very satisfying heft to it!  And it was oddly fun to build!

Thanks for looking in on me,
Kim

[crueby]

Thats Grate!   (got the pun in first!)   

More excellent work!

[Kim]

Thanks Chris!   

I'm sorry to be the bearer of bad news, but CNR beat you to the pun(ch) a few posts back.  If you look in post 1921 you'll see that he used the grate/great pun a few days ago.

But a good pun is good even the second time around, right? 

Kim

[crueby]

Thanks Chris!   

I'm sorry to be the bearer of bad news, but CNR beat you to the pun(ch) a few posts back.  If you look in post 1921 you'll see that he used the grate/great pun a few days ago.

But a good pun is good even the second time around, right? 

Kim

Ah, well, I'll keep trying!  And watching along!   

[cnr6400]

All I can say Chris is that I was makin puns and you was probably makin parts!  (very nice parts, as usual,  I might add) 

That day I was up early and ate some weeties, too 

[Kim]

That day I was up early and ate some weeties, too 

No wonder they were EXTRA strong puns that day!

Kim

[Kim]

OK, quick question for you all...

Are my pictures too big?  I know the download size isn't too large. I keep them around 100K or so by using 85% quality on the JPG rendering, but it keeps the detail quite well, I think. But I use 1024x768 as my standard resolution.  Is that too big on people's screens?  Is it annoying? Or does it provide better detail?

I could easily back off to 800x600 if that would be better.

I find 640x480 a bit on the small side for my tastes, but if that's what people prefer, I'd be happy to do that.

I've just started realizing that my images are larger than other people's and I decided it was time to do something about it.  Either change size or not worry about it.

So I thought I'd ask.
Please do provide your candid feedback, I'd greatly appreciate it!

Kim

[cnr6400]

Pic sizes you are using are just fine here Kim, thanks!

[crueby]

They look fine and download quick on both my tablet and PC.

[Michael S.]

Hello Kim, the size of your pictures is absolutely fine. Even for me. I do everything on the internet just with the mobile phone and it works fine.

Michael

[Admiral_dk]

As I recesntly mentioned in another thread - I love them BIG .... and more and more so the Older the Eyes get 

I enjoy your pictures - they are easy to look at and see the details 

Per