Author Topic: Pennsylvania A3 Switcher (Kozo)  (Read 327518 times)

Offline Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1875 on: September 18, 2022, 05:49:17 PM »
Thank you, Chris!  :cheers:
You're really on top of things today!  ^-^
Kim
Just Dumbus Luckus (latin for good planning?  :Lol: ) that I happened to click on the page and reply just after you posted.
I like that!
I think I do a lot of 'Latin planning' myself  :ROFL:

Kim

Offline Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1876 on: September 18, 2022, 10:15:20 PM »
This morning my 1/4-32 die arrived!  So I finished up the pump body:


Now, to finish up the plunger.
All that’s left is to cut a 3/32” Stainless rod to length and cut a little nubbin on it to fit in the 1/16” hole in the crank bearing.  So I did that.  It was so easy I forgot to take pictures.  But there it is, ready to be glued together.


Kozo recommends Loctite for these items.  Not sure why he didn’t silver solder them. I considered it but decided he may have his reasons. One possible reason that I came up with was that heating up that tiny rod might cause it to warp some, which wouldn’t be good for this application.  But who knows?  Regardless, I went ahead and used Loctite.


And that completes the plunger for the lubricator pump.

Kim

Offline Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1877 on: September 18, 2022, 10:19:33 PM »
Chapter 21.6 – Crank
Now I’ll tackle the crank.

I made the crank disk from a scrap piece of 3/8” 303 stainless steel rod.  I turned it down to the specified 23/64” and drilled the middle hole to be tapped 5-44. (no pic... I forgot!  :embarassed:)

But before I tapped the hole, I moved the part and collet over to the mill (in a square collet block), Indexed off the center hole, and drilled and reamed a 1/16” hole for the crank pin.


Back to the lathe, I then tapped the center hole (5-44), then cut off the part.


Then I cut a short length of 1/16” piano wire for the crank pin.  Kozo recommends cutting the shank of an appropriately sized drill to use for the crank pin, but I chose to go with the piano wire believing it to be plenty hard for this application (not to mention it won’t ruin one of my drill bits!)


And finally, the two parts are cleaned and Loctited together.



And with that, I was ready to come in for a late lunch.
Thanks for stopping by for a visit!
Kim

Offline cnr6400

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1878 on: September 19, 2022, 04:44:53 AM »
 :ThumbsUp:  :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :popcorn:
"I've cut that stock three times, and it's still too short!"

Offline Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1879 on: September 19, 2022, 10:57:39 PM »
Thank you, CNR!  :cheers:

Kim


Offline Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1880 on: September 19, 2022, 10:57:49 PM »
Chapter 21.7 – Ratchet Wheel

Today I’m focusing on the ratchet wheel.  This wheel is slowly turned by the movement of the eccentric rod and the ratchet keeps it rotating in the forward direction.

I took a piece of 1/2" W-1 steel, turned it to the required size, then move it into a collet spinner.  This lets me index my way around the wheel cutting ratchet teeth, like so:


With the teeth cut (there are 20 of them) I moved it back to the lathe, drilled and reamed the center hole then cut it off to width.


Kozo recommends heat-treating the ratchet wheel, so I did that next.  I learned this technique from Dave Otto – suspend the part being heat treated by a magnet over the water, then heat it up.  When it gets hot enough for heat treatment, it becomes non-magnetic and falls off into the water.  This method works quite well!


Then I turned the short shaft for the ratchet wheel (no pictures of that).  Here are the two parts, the shaft, and the ratchet wheel.  I’ll wait to Loctite it together till I get further along, to make sure I get it attached in the correct place.


And that’s it for today’s update.
Kim

Offline crueby

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1881 on: September 19, 2022, 11:07:20 PM »
Neat trick with the magnet!

 :popcorn: :popcorn: :popcorn:

Offline cnr6400

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1882 on: September 20, 2022, 01:19:07 AM »
I remember back in the 1980's a writer for Live Steam magazine, Chas. O C Darling, mentioned he hung a bar magnet from a string in his shop. This was used to test the attraction, or lack of it, on red hot bars of steel, for the same purpose of knowing when it was ready for quenching. It's an old and very useful technique. Mr Hiraoka knows all the tricks!

 :ThumbsUp: :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :popcorn:
"I've cut that stock three times, and it's still too short!"

Offline Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1883 on: September 20, 2022, 05:05:06 AM »
Thanks Chris & CNR!

I remember back in the 1980's a writer for Live Steam magazine, Chas. O C Darling, mentioned he hung a bar magnet from a string in his shop. This was used to test the attraction, or lack of it, on red hot bars of steel, for the same purpose of knowing when it was ready for quenching. It's an old and very useful technique. Mr Hiraoka knows all the tricks!

Yes, he certainly does!  However, to give proper credit, I learned THIS trick from Dave Otto, on our forum!   

Kim

Offline Roger B

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1884 on: September 20, 2022, 07:14:21 PM »
I also use the magnet trick for hardening small parts.  I'm not sure how good it is on thicker sections  :thinking:  :headscratch:
Best regards

Roger

Offline Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1885 on: September 20, 2022, 09:19:04 PM »
Yeah, I could see how with a bigger part you might not be getting the whole thing up to temperature.  But the technique does seem to work pretty well for these little parts!

Kim

Offline Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1886 on: September 20, 2022, 09:19:51 PM »
Chapter 21.8 – Bushing and Nut

Only a little time in the shop today but I managed to turn out a couple of small parts.  The bushing to hold the lubricator crankshaft in the pump housing, and the nut to fasten it with.

Both parts were turned from 5/16” hex brass stock. Very easy and quick:


Not a lot, but a little progress nevertheless!
Kim

Offline Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1887 on: September 21, 2022, 10:22:45 PM »
Chapter 21.9 – Pawl Bracket and Lever

The next parts for the lubricator are the Pawl Bracket, which as the name implies, will hold the spring pawl for the ratchet wheel, and the Lever, which will connect the eccentric rod to the ratchet wheel.

The pawl bracket is fairly simple. The only thing that complicates it is the small size and the fact that all of its dimensions are non-standard, so I had to mill all sides to get the correct sized block.  It started as a 1/2" length of 1/4" x 3/8” 1018 CRS but was finished down on all sides

But after that, it was just drilling 2 mounting holes (close fit for #0 screws):


Then drilling and tapping the mounting holes for one of the spring pawls:


And here’s the little puppy after machining:


The lever isn’t much more complex.  It was made from 5/16” square 12L14 stock.  After trimming to length, I drilled and reamed a 1/8” hole for the ratchet wheel shaft on one end, and a 5/64” hole for the pin that will mate with the eccentric rod on the other.  Only the 1/8” hole has been completed here:


On the side, I drilled and tapped two 0-80 holes for the other spring pawl.  You can also see where I did some marking on the part.  Not for accuracy, but to make sure I put the holes and notches in the correct places.  This part is NOT symmetric in any way.


Lastly, I cut the notches out of either end of the lever.  One notch is for the ratchet wheel and the other for the eccentric rod.


And that wraps up the lever:


Couple more pieces complete!
Kim

Offline cnr6400

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1888 on: September 22, 2022, 02:55:55 AM »
 :ThumbsUp: :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :popcorn:
"I've cut that stock three times, and it's still too short!"

Offline Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1889 on: September 22, 2022, 10:37:12 PM »
Thanks CNR!  :ThumbsUp: :cheers:
Kim

 

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