Author Topic: Pennsylvania A3 Switcher (Kozo)  (Read 104785 times)

Offline Dave Otto

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1170 on: August 13, 2021, 11:20:07 PM »
That does look quite nice Kim!

Dave

Online Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1171 on: August 14, 2021, 05:20:26 AM »
Nice soldering work Kim, that came out really well. What is the pickle you are referring to? A basic passivation of some sort?
Thanks Stuart!

The pickle bath is a mild acid solution that helps remove the flux and clean the part that's been soldered.  You should wash the part after pickling to rinse off the mild acid.

I've been using Sparex as my pickle solution.  It's safer than the traditional sulfuric acid based pickles anyway!

Kim

 

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1172 on: August 14, 2021, 05:20:51 AM »
Thank you Dave!
Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1173 on: August 14, 2021, 11:44:21 PM »
My next step was to drill the steam passages.  To mark their location I clocked in the part on the mill and marked the spot for both the inlet passage and the exhaust passage on the top.  Sorry, no picture. Guess I forgot.

I took it to the lathe and dialed it in the steam input spot using the 4-jaw.  I even started to do this before I remembered to take a pic!


I turned a spigot where the steam input pipe will be attached.


And drilled the steam inlet passage all the way through the Tee.  I started with one of my better (read more accurate) drills, but they are all screw-machine length, and I needed something quite a bit longer to reach all the way through the part. So I broke out my el-cheapo Harbor Freight jobber length bit set and used that to finish up the last inch or so of the through-hole.


Here Iíve just drilled a little wide spot in the end Ė I believe this is to receive the olive in the compression connection with the input steam pipe.


And finally, I cut the 5/16Ē-24 threads into the steam input spigot.


Iíd carefully added a center spot for the exhaust in my first step, but then my next step (cutting the inlet spigot) shaved that right off.  So, back to the mill to re-create the exhaust location.


Now, back to the lathe, same setup, just centered on the exhaust spot this time.  And drilling an H hole all the way through.


Then I drilled the tapping size for 5/16Ē-24 and threaded the exhaust connection.


And that was where I stopped today.  Tomorrow Iíll work on the cross holes for the steam and exhaust passages.

Thanks for stopping by!
Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1174 on: August 14, 2021, 11:47:37 PM »
Hi Kim

Nice set ups!   Is that a roll tap?

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Online Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1175 on: August 14, 2021, 11:55:43 PM »
Thanks Dave,

Yeah, that's a forming tap.  I went through a phase where all the taps I bought were roll-form taps.  I found them to be a little stronger and work well in softer metals.  But lately, I've found that if I get a good cutting tap (like Union Butterfield spiral-tip or something) that they work really well too.  I just have to be careful which kind of tap I have so that I use the right hole size (for cutting or for forming).   ;D

The only downside I've found to the roll form taps is that you tend to get a little mound pushed up around the hole that you have to file down or have a nice big chamfer there from a hole reamer or something.  Not a big deal, but something you have to take care of.

Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1176 on: August 14, 2021, 11:59:09 PM »
Interesting!    I am considering a roll form tap for the con rods on the 12, for added strength.   something to keep in mind

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline crueby

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1177 on: August 15, 2021, 12:09:15 AM »
Interesting!    I am considering a roll form tap for the con rods on the 12, for added strength.   something to keep in mind

Dave
Roll form taps add strength?

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1178 on: August 15, 2021, 12:21:43 AM »
I'm to understand that they do as the threads are formed....not cut.   so they have better performance.

.....Anybody have some paper on these?

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Online Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1179 on: August 15, 2021, 05:20:52 AM »
No paper, sorry.  But I have heard that they work harden the threads as they are making them since they are pushing the metal around.  Don't know how significant that is, but that's the non-substantiated info I remember hearing :)

Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1180 on: August 15, 2021, 01:52:22 PM »
A bit long winded  :Director:  , but Parker Hannifen have been producing their 3H series of hydraulic cylinders in the US for 50 years plus, which alll include tie-rods with rolled threads

So the bar stock is undersized, then the threads rolled up to size, and as Kim says ....'the metal is moved around'

So this eliminates the sharp thread cut V in the root or valley of the thread, replacing it with a rolled V profile with a rounded root profile and mirror polished thread faces

All a bit subjective, the thread rolling does produce that mirror thread surface, so by increasing skin hardness on the thread face which can reduce galling, however the rolling process does not alter the mechanical properties of the heat-treated bar stock

There are no Wifes Tales here :Lol:    , however have not seen any low production of rolled threads  :killcomputer: as commercially available

https://www.parker.com/literature/Industrial%20Cylinder/cylinder/cat/english/HY08-1114-6_NA_2H-3H%20.pdf

Derek
« Last Edit: August 15, 2021, 02:13:13 PM by derekwarner »
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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1181 on: August 15, 2021, 02:18:30 PM »
Thanks Derek.

I'm going to carry this subject on over in the tools thread, so as not to muddy up Kim's build, but I'd like to talk about it for sure!

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Online Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1182 on: August 15, 2021, 11:27:48 PM »
Thanks, everyone. I certainly wouldn't worry about muddying up my thread :)  But it probably will make it easier for people to find in the future :)
I love these kinds of conversations.  I learn so  much!
Kim

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1183 on: August 19, 2021, 12:05:13 AM »
To finish up the steam passages in the Tee, I started in the mill by marking the locations for drilling.  While in the mill I also spotted and drilled the 5-40 clearance holes for the mounting screws (which will mate with the cylinders).  The black circle is to help me remember that the marked hole is the exhaust hole and should be the larger of the two.


Now, Kozo shows drilling these passages in the lathe, but since Iíve got it all set up nice and square in the mill, I decided to go ahead and do it here.  In Kozoís process, you havenít squared up these passage faces yet.  But I did that some time ago in my process.  So they are square with the world and parallel to each other.  I figure it would be easier just to do it here and should work just as well, as long as I can keep the holes square with everything.  And it seems to have worked just fine.

So, I drilled the steam inlet hole clear to the center, to meet the through-hole drilled on the lathe (upper rightish hole). Then did the same to the exhaust passage (lower leftish, larger hole).  I then flipped it over and did the same to the other side.


With the steam passages and cylinder mounting holes drilled, I wanted to make sure things were lining up properly.  So I connected it up to the cylinders.  To do this I ended up having to grind down one of my 5/32Ē hex keys.  The space in there is pretty tight (and even more so on the other side with the upright part of the Tee in the way.


And hereís the Tee spanning between the two cylinders.  The Teeís not done yet. Still more shaping to go. You canít quite see it in this photo, but the frame mounting holes along the other side of the cylinder are covered up by the mounting flange of the Tee.  I need to shave those down so it doesnít get in the way of the mounting holes (and so it fits in the pentagonal holes in the frame.)


Doing this calls for some hefty 45o chamfers on the mounting flanges.  For this setup I used some little V-blocks underneath, to hold things at 45o.  The V-block was held in the vise to keep it square with the mill.  To clamp the part in place for milling I used another 45o block on top (Iíd made this for some other purpose in the past).  The thing on top of the 45 is a 30o block, but itís just used as a spacer so that the clamp is above the Tee upright when itís facing up (which it will be for some of the cuts).  Here you can see Iíve milled off one of the front corners of the Tee flange.


And hereís after all four corners have been removed (note, they are not symmetrical Ė this IS intentional.)


After doing the other side I tested in the frame window and had that happy feeling because it fit!  :cartwheel:


As Kvom mentioned earlier, the Tee has to fit between the frame and then hook up to both cylinders.  I thought I could just wiggle it into place and then attach the cylinders.  Not the case.  It wonít be wiggled into place. Iím going to have to take the frame apart to get the Tee in place  :-\


But it should fit at least.  I did check :)

However, the Tee isnít quite finished yet.  I still have some work on the bottom to do.  I have to shave it down by 1/16Ē and add some mounting holes for the steam and exhaust deflectors.

Thanks for looking in,
Kim

Offline crueby

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Re: Pennsylvania A3 Switcher (Kozo)
« Reply #1184 on: August 19, 2021, 12:16:20 AM »
Great progress, looking excellent!  I can see why you label things, bet that its very easy to get ends/directions confused on those shapes.

 :popcorn: :popcorn: :popcorn: