Author Topic: Pennsylvania A3 Switcher (Kozo)  (Read 357851 times)

Offline Admiral_dk

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #4020 on: May 11, 2024, 11:07:08 AM »
Ta da da dah - and now Kim has a Locomotive (it certainly looks like one)  :praise2:

Per     :cheers:

Offline RReid

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #4021 on: May 11, 2024, 12:49:21 PM »
Very nicely done, Kim. The cab looks great! :cheers:
Regards,
Ron

Online Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #4022 on: May 11, 2024, 04:26:15 PM »
Thanks Per and Ron!  It's getting close to being a real loco!  ;D

Kim

Offline Roger B

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #4023 on: May 12, 2024, 06:59:59 AM »
Chuff Chuff Chuff  :)  :)  :)  :praise2: Almost there  :wine1:
Best regards

Roger

Offline Firebird

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #4024 on: May 12, 2024, 04:47:45 PM »
 :ThumbsUp:

Looking good

Cheers

Rich

Online Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #4025 on: May 12, 2024, 05:06:24 PM »
Thanks, Roger and Rich!  Still, a ways to go yet, but I'm gaining on it!

Kim

Online Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #4026 on: May 13, 2024, 11:11:00 PM »
Chapter 32.6 – Air Reservoir

Now for the Air Reservoir.  In this model, the Air Reservoir holes a battery, rather than compressed air.  Kozo designed it to hold a single 1.5v C cell battery.  However, the LEDs I’m using require about 3V, so Kozo’s battery holder won’t work for me as is.  If you recall from past ramblings in my blog (post 3286, in case you want a refresher) I have decided to use one of those little round holders used in many flashlights that hold 3 AAA cells and provided 4.5V.  I have many of these flashlights sitting around so I took a couple of them that weren’t working and scavenged the battery holders out of them.  I liked the clearish one the best because it has a spring on the end for one of the contacts.  But one of the internal contacts broke during cleaning (many of them are old enough that the batteries corroded and leaked, which is likely why they weren’t working).  So I have chosen to use the black one (the one with the batteries in it).  If this one isn’t satisfactory, I’ve got a few more flashlights I can scavenge from.  And if all else fails, I have seen them listed on Amazon for just over a buck each.  But might as well be frugal if I can, right?  I’ve got a C-cell sitting there for comparison.


Now, the 3-cell AAA holder is pretty close in size to a C cell it isn’t exactly the same.  The C cell is about 1” in diameter and just under 2” long.  The AAA battery holder is about 0.9” in diameter and about 2 1/8” long.  The diameter is an easy one to solve. The length took a little more head scratching.  In the end, I’m going to make the whole reservoir about 1/8” longer and shave a 1/64” of the inside of the top and bottom caps.  This should make up for the difference in length.

The main body of the reservoir was made from 1 1/4" 12L14 round rod.  After facing it off I drilled a hole all the way through the part, stepping up in size till I got to 7/8”.  Then I bored it out a bit more to 0.920” (the general size of the inside of the flashlights I got the battery holders from.)



After boring, I flipped the part around and faced the other side off to length, which for me was 2.5” (for Kozo it was 2.375”).  And here’s the main body up to this point:


You can see how the battery holder will slide in there nicely.  You can also see that I didn't get a great finish on my bored hole, likely because I had to have the bar stick out so far from the tool post.  I could have made it look nicer but I don't much care since nobody will see that.  It just has to hold the batteries.

There are still a few holes to drill in this cylinder to hold the caps on. But this is as far as I got today.  It’s a short update but I didn’t want to leave it all to the end of the week like I did last time and have an over-long update.  I much prefer more frequent shorter ones.

Thanks for looking in!
Kim

Offline crueby

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #4027 on: May 13, 2024, 11:25:25 PM »
Enlightening post!   :Jester:
Given the tendancy for batteries to poop inside electronics, be sure to take them out of the holder when not showing it! I've had batches of alkalines that leaked while still in the box, 2 years before the expiration date on the package.

Offline Krypto

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #4028 on: May 14, 2024, 02:36:48 AM »
Pooping alkaline batteries is why I use rechargeable batteries (Eneloop for AA nowadays) whenever possible.  Can't say I've had any of that type leak in the few decades or so I've been using them going back to Nicad's.  Of course you need to account for the lower cell voltage.  I've even started using rechargeable 9V's with good success.

Today's alkalines seem to be just horrible.  I use them in clocks (smoke alarms too) and that's about it as usually they will drain before they leak.
My Workshop Blog:  https://doug.sdf.org/

Online Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #4029 on: May 17, 2024, 10:14:57 PM »
Carrying on with the Air Reservoir/Battery holder, I drilled two holes in each end to secure the end caps.  The holes were to be on opposite sides from each other so I just drilled each pair in a single operation:


Then I went back and made a countersink in each hole for a #2 screw head.


Now on to the end caps.  The idea is to make a little dome for each end of the main cylinder.  I made the top and bottom caps on either end of the long 1.25” bar stock (12L14 – same bar as was used for the main body).  That way it was easier to hold and I could do the operations to both the top and bottom cap as I went along rather than having to repeat each setup.

I turned a boss first, which will fit inside the hole in the cylinder.  Then I drilled and reamed a center hole for the positive battery terminal assembly.  (This is the top cap, by the way.  The bottom cap is just a little bit different.)


Then I made a larger 3/8” relief in the center, also for the positive battery terminal assembly.  We’ll see how that works a few posts down the line when I get to that.


Next, I drilled the matching screw holes in the end cap using the holes in the body as a drill guide.  I first made a dimple using the clearance drill that matched the size of the hole in the main body, then switched to a smaller drill for the hole in the cap.


Then threaded it 2-56.


Just one more shot so you can see how things were fitting together so far.


I did one hole first, then with the screw in place, I proceeded to make the opposite hole to keep things in alignment.


With the screw holes complete, I used the band saw to cut the end caps off the parent stock.


Kozo doesn’t give any radii for the curves, so I just made up a curve that I thought looked pleasing, and about like the drawings. Then used Excel to made a step-off chart to help approximate that curve. 


I held the turned boss in a collet which allowed me to access the dome side of the part.  Here’s what it looks like after I used my step-off chart.  Lots of cute little stairsteps.


Then I went at it with some files and sandpaper and here’s what it looked like when done. This is the bottom dome, BTW.


Here are all three pieces to this point.  Left to right; bottom cap, main body cylinder, top cap.


And what it looks like assembled.


The top cap isn’t complete yet.  I still need to make a bracket that will be silver soldered to it.

That’s all for today.  Thanks for looking in.
Kim

Offline crueby

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #4030 on: May 17, 2024, 10:40:45 PM »
Great looking tank!   :popcorn: :popcorn:

Online Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #4031 on: May 18, 2024, 05:22:37 AM »
Thanks Chris!  :cheers:

Yeah, the only thing really tricky about this is I'm going off-script and redesigning parts of this to work with my version of the battery.  Hopefully, it will all work out in the end!.
Kim

Online cnr6400

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #4032 on: May 18, 2024, 03:39:10 PM »
 :ThumbsUp: :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :popcorn: The tank looks great Kim! Nice job.  :cheers:
"I've cut that stock three times, and it's still too short!"

Online Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #4033 on: May 18, 2024, 04:37:43 PM »
Thanks Jeff!  :cheers:
Kim

Offline Dave Otto

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #4034 on: May 18, 2024, 06:01:05 PM »
The tank looks great Kim, nice work!
Sometime could you give me tutorial on how to create the step off sheet in Excel? If it is not a standard fractional radius that is in Guy Lutard's book, I will draw and dimension CAD which is quite laborious.
Most recently I did the two lumps on the push rod of my friends early Deutz inverted engine that I have been working on.

Thanks
Dave

 

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