Author Topic: Pennsylvania A3 Switcher (Kozo)  (Read 71907 times)

Offline Don1966

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1005 on: April 07, 2021, 10:52:36 PM »
Another step compete and well executed. Looking great Kim.....  :Love:



 :cheers:
Don

Offline Dan Rowe

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1006 on: April 07, 2021, 11:33:17 PM »
Something I've been meaning to ask - does anyone know where you can get some 3.5" track?   I've looked around some and haven't found too many options.  At one time, I found a place where you could get a track-shaped piece of steel (I-beam kind of thing) that was scale size for 3/4" - it was like a 6 or 8 foot length. But I can't find that now.  I'd take pre-made track sections too, but I haven't been able to find that.

Any pointers would be very welcome!
Kim
Kim how much rail do you need? Jason only has G1 track in his store. The rail is listed as code 250 for Sunset Valley track this means the rail is .25" tall. LBG track is code 332 or .332" tall. For most G1 scales code 332 is huge. (elephant track)

It is common to use 1" tall rail for 1.5" scale so .5" or .625" would be good for 3/4" scale.
Here is a link to a discussion about 3.5" track:
http://www.chaski.org/homemachinist/viewtopic.php?t=83559
Here are some possible sources of rail and more ideas, the groovy rail system uses flat steel sections with slots cut in the ties to support the rails similar to the tube spacers used in the first link.
http://ibls.org/mediawiki/index.php?title=IBLS_Track_Standard

I found 3.5" track on EbayUK but the shipping was more than the track.

Cheers Dan
ShaylocoDan

Offline crueby

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1007 on: April 08, 2021, 12:02:09 AM »
Dan is right, there are a lot of different sizes, depending on scale of model, narrow vs standard guage, all that. The stuff I used for the Shay base is the 250 code, this is what it looks like with the model. May not be totally accurate, but it looks nice for display.



Offline Dan Rowe

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1008 on: April 08, 2021, 02:48:58 AM »
Here is a link to rail used in the US and the major railroads are listed. This works for scale tracks.
http://www.icrr.net/rails.htm

If this rail is for ride on live steam tracks the rail has to be sized for the load which is the big folks on the train so that is why 5/8" rail seems to be the choice.

The Pennsylvania RR used 5" 0r 5.5" rail so code 332 rail would work well for scale rail.

Chris code 250 rail works out to about 50 pounds per yard which is I think works but I did not check my Shay catalogs.

Cheers Dan
ShaylocoDan

Online Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1009 on: April 08, 2021, 05:25:02 AM »
Wow!  Thanks Matthew, Chris, Dan, for the great comments on where to find track.  I'll have to look into these various sites.  Lots of good info here!

Thanks Don, for the encouraging words!

Kim

Offline Barneydog

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1010 on: April 13, 2021, 09:00:02 PM »
Hi Kim,
Jumping back a page to your quartering. Nice Jig you made. My jig is made from wood and will suit any wheels upto 7" and any size axles and pins. You saw it in my Sweet Pea posts but I did not give much detail as it is being printed in the next issue of Engineering in Miniature mag.

There is nothing wrong with wood....why waste ali?  So long as all your wheels are quartered on the same jig and match they will be ok. Ninety degrees is the preferred but if they are 88 or 92 it does not matter as long as ALL the axles are identical. You will soon know if they are not!

Cheers

Julian

Online Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1011 on: April 13, 2021, 11:55:18 PM »
Thanks Julian!

Once I get the side rods done, THEN we'll know :)

Kim

Online Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1012 on: April 16, 2021, 10:55:23 PM »
I’ll apologize in advance for the length of this post – I’ve been working on the side rods and they were complicated beasts! It’s taken me almost two weeks to finish these guys.  In addition, I got my 2nd shot and that took me out for a day or so.  Anyway,  here it goes...

The side rods were made from lengths of 1/4" x 3/4" 1018 CRS.  Before machining, I stress relieved them by heating them up with the torch till they were nice and cherry red all over.  After keeping them hot for a while so they got a nice soak, I let them cool slowly. This is my attempt to keep them from going banana-shaped when machined.



While the parts were cooling, I made a 7/16” counterbore. This will be needed for the side rods in a future step.  The guide is 9mm (0.3543”) and the upper part with the cutter is 7/16”.  I made it a single tooth cutter hoping it would work OK. And it did – not excellent, but good enough.  I tried to file in a little relief in the single tooth then harden the steel (this was done with W-1 tool steel).  Also, that little divot right in the tip of the guide is a mistake.  I didn’t have the mill pulled back far enough while I was setting the height.  Ah well – I just made sure to file that down so there wasn’t a sharp edge.  Didn’t really affect the performance of the tool.



After the stress relief, I needed to machine the 1/4" width down to 0.200”.  I first tried the face mill, but I didn’t like how that sounded with the interrupted cut.


So I switched to using my standard method for this kind of op.  I took some off of each side, then went back and did one final pass of a few thou on each side.  They stayed nice and straight.  So the strain relief and the symmetrical operations on each side must have helped (he says optimistically).


Next, I blued the parts and did a little layout work.  Here are the two nascent side rods, the drilling jig, and the 7/16” counterbore.  You can see how it will be used to create the counterbore shown in the A-A section drawing on the right side of the sheet.


Now to use the drilling jig.  First, I drilled and reamed one of the 9mm holes.


Then, using the drilling jig that I’d set previously, measured out exactly where to drill the second hole in the side rod.  As it turns out, it was EXACLTY 5.5000”.  :) Go figure.  I could have skipped the whole drilling jig after all!  But now I know for SURE that my processes were tight enough that I ended up where I expected.  Not always the case, but this time, it worked out.


After drilling and reaming both holes, I lined up the two side rods, back to back, using a 0.354” gauge pin and the guide on the counterbore, then clamped them in the mill vice and milled a rough top profile in the parts.  I did actually remove the counterbore before I did the milling.  I just put it back in for this picture.


Following this step, I counterbored the outside front hole in each side rod.  As of this step, the side rods are officially left and right-handed.  They are no longer interchangeable.


You can see the basic profile in the rods here.  And see that one rod is LEFT and the other is RIGHT.


To round the ends of the rod, I used the rotary table.  I zeroed in the center of the table, then positioned one of the end holes directly over it using the 0.354” gauge pin, and clamped it in place.  With that, I plunged a 1/4" mill around the outside edge of the circle – about 20 thou bigger than my final size.  (I did a bunch of trigonometry before this to know what angle to start and stop each of the sections – and I was pretty close!)


Then I went in and took off the peaks and the final few thou just rotating the RT.  The final cut was climb-milled to give a better finish.


All four holes rounded off.


The next step is to take the sides down to size.  For this operation, I needed yet another simple jig.  This one required a couple of bushings – 9mm bushing with 1/4" holes.


I drilled and tapped (1/4 – 20) two holes in a length of 1”x1” aluminum stock.  This lets me securely hold the side rods on edge so I could bring the width down to the required 1/8”.  Here it is all set up waiting for the first side to be carved:


And just after the first side was carved.  I was only taking off about 37.5 thousandths, but I did it in a few passes, with the last pass being a small climb cut.  Notice that I left about 1/8” along the bottom at full width.  This is to provide additional rigidity while machining the other side.


Then I flipped the rod around in the jig, put a few shims behind the cut-off portion to help give it additional rigidity, and milled off this side exactly the same as the first.


Here’s the current profile of the side rods after that last step.


Back into the holding jig, but on its side this time.  I used a roughing mill to take off the bulk of the material that was left after the last step.  I deviated from Kozo’s instructions here.  He says to use a slitting saw to take off that portion, but I couldn’t figure out how to get a slitting saw in there without damaging the round holes on each end.  So I just went with milling it off.


Switched to a standard mill for the last few passes.


To clean up the tooling marks, I wrapped some sandpaper around a 3/16” rod and slid the Jig back and forth. This helped to clean up all four sides (though on further review, I think I need to do more sanding).


The last step is to drill and tap holes in each end of the side rods (2-56).  I assume these are oil holes, though it doesn’t ever quite say.  And I’m not sure why they are taped.  Nothing ever screws into these holes that I can see.  Maybe it just helps with making the oil drain more slowly or something?


And the final beauty shot of the side rods.


Thanks for sticking with it through the end!  It was a long story, but a lot happened :)

And thanks for checking in with me,
Kim


Offline crueby

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1013 on: April 16, 2021, 11:05:04 PM »
Great sequence, worked great!  On the counterbore, did you harden/temper it?

Offline Barneydog

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1014 on: April 16, 2021, 11:08:21 PM »
Hi Kim,

Looking good. Retirement is starting to pay off!!

Cheers

Julian

Offline joe d

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1015 on: April 16, 2021, 11:13:04 PM »
A lot of work in those parts.  Came out excellent!

Joe

Offline 90LX_Notch

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1016 on: April 17, 2021, 12:36:18 AM »
Nice work on the rods Kim.

-Bob
Proud Member of MEM

My Engine Videos on YouTube-
http://www.youtube.com/user/Notch90usa/videos

Offline Dave Otto

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1017 on: April 17, 2021, 12:40:50 AM »
Nice work Kim!  :ThumbsUp:

Offline RReid

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1018 on: April 17, 2021, 12:57:31 AM »
That's really nice work Kim, both the parts and the write-up.

It would seem that those little tapped holes would be for a small oil cup, but when I reviewed my copy of the book the bushings aren't shown as being drilled, so oil wouldn't get through anyway. Maybe a dummy oil cup was intended? I couldn't find a single photo or drawing showing the side rods assembled in anything other than a "rods down" position, in which case that area is always hidden from view. I imagine you looked too, but I got curious.
Ron

Offline Craig DeShong

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1019 on: April 17, 2021, 03:25:52 AM »
Great looking side rods  :ThumbsUp:
Craig