Author Topic: Pennsylvania A3 Switcher (Kozo)  (Read 327523 times)

Offline Kim

  • Global Moderator
  • Full Member
  • *****
  • Posts: 7860
  • Portland, Oregon, USA
Re: Pennsylvania A3 Switcher (Kozo)
« Reply #495 on: November 17, 2019, 05:57:32 PM »
Thanks, Jo, Bill, and Mike,
Appreciate the comments!  :)
Kim

Offline Kim

  • Global Moderator
  • Full Member
  • *****
  • Posts: 7860
  • Portland, Oregon, USA
Re: Pennsylvania A3 Switcher (Kozo)
« Reply #496 on: November 24, 2019, 01:48:42 AM »
Continuing on with the Horseshoe Assembly (the place where the coal sits before its shoveled into the boiler).

Next step was to file the vertical board flush with the bottom of the Bottom Horseshoe Bracket.


Here we are, all nice, flat, and flush!


Then I mounted the horseshoe assembly onto the floor of the tank.  All the holes lined up well, and I was thankful for that!  However, I discovered that one side didn’t line up the way it should have.  The edge circled in red should line up with the edge circled in blue.


Here’s a shot straight on from the side that might show better what I mean.  The red arrows point at the edge on the horseshoe, in the back.  And the blue arrows point at the edge of the copper side. Those two edges should line up, but the inside edge (marked in red) is about 40-50 thou off.  Not sure why, but it is.


So, I decided to cut the inner edge down a little to make it match.  I considered filing it, but that would have been hard for me to keep it straight, flat and uniform. So I decided to mill it down.  But to do that, I needed to make an appropriately sized wood spacer.  And to do that, I needed to use my table saw.  But before I could use my table saw, I needed to finally get around to cleaning it up.
As it turns out, a couple of months ago, our water heater went out.  And for some reason, they thought it was a good idea to put the house water heater in my shop!  Go figure!  (Well, sure, my shop is in the garage, but really, how inconsiderate!) So when our water heater went, it was leaking water all over the floor of the garage.  Nothing got seriously damaged, but in the hubbub, some wet items got sat on my table saw (since it was a nice, inviting flat surface).  A week later when I noticed, there was a nice layer of rust on the tabletop.
So, today, I took some oil and some steel wool and went to work.  Then I got smart and used a scotchbrite brush in my drill to speed the process up.  It worked pretty well. What you’re seeing on the table saw is the brown sludge that is created when the oil is mixed with the rust.  The table didn’t look THAT bad!  But after about an hour I had that cleaned up.


Here’s my setup for shaving down that edge on the horseshoe assembly.  You can see the piece of wood I cut to act  as a spacer in the open space between the sides of the horseshoe. The piece was clamped down well, but since it was so far from the support I took very shallow cuts. And I’m only cutting brass, so it worked out quite well.


Following that, I cut the inner wall, leaving 0.040” sticking up so it will mate up with the tank wall piece that will be coming next.


then, I filed the square corners round, leaving the same 0.040” flange around the edge.


And finally mounted the horseshoe assembly back in its place.  Things line up much better now!






So that’s it for the Horseshoe assembly.  Next up will be the front plates that cover the gap between the sides and the horseshoe assembly.

Thanks for checking in,
Kim

Offline Flyboy Jim

  • Full Member
  • ****
  • Posts: 2002
  • Independence, Oregon
Re: Pennsylvania A3 Switcher (Kozo)
« Reply #497 on: November 24, 2019, 03:02:23 AM »
Nice result Kim.  :ThumbsUp:

Thanks for the nice "back story" on how you got this accomplished. One thing I've learned about model machining is that there are always a lot of "back stories" involved in the process of machining a part!  :shrug:

Jim
Sherline 4400 Lathe
Sherline 5400 Mill
"You can do small things on big machines, but you can do small things on small machines".

Offline Kim

  • Global Moderator
  • Full Member
  • *****
  • Posts: 7860
  • Portland, Oregon, USA
Re: Pennsylvania A3 Switcher (Kozo)
« Reply #498 on: November 24, 2019, 05:32:07 AM »
Thanks Jim,
So true!  There's always a story that goes into every part.  And that's what I find so fascinating about this site is that I get to learn how others tackle making things.  Each part has its own challenges, and I learn so much from reading everyone else's posts!
Kim

Offline Roger B

  • Global Moderator
  • Full Member
  • *****
  • Posts: 6133
  • Switzerland
Re: Pennsylvania A3 Switcher (Kozo)
« Reply #499 on: November 24, 2019, 07:34:00 AM »
That's some excellent fabrication  :praise2:  :praise2:  :wine1:
Best regards

Roger

Offline mike mott

  • Full Member
  • ****
  • Posts: 418
  • Alberta Canada
Re: Pennsylvania A3 Switcher (Kozo)
« Reply #500 on: November 24, 2019, 10:59:01 PM »
Nice save on the fit.

Mike
If you can imagine it you can build it

Online cnr6400

  • Full Member
  • *****
  • Posts: 2728
Re: Pennsylvania A3 Switcher (Kozo)
« Reply #501 on: November 25, 2019, 12:02:37 AM »
 :ThumbsUp: :ThumbsUp: :ThumbsUp: Great repair Kim! that one could have gotten very involved if it were off a few thou more.  :cheers:
"I've cut that stock three times, and it's still too short!"

Offline Kim

  • Global Moderator
  • Full Member
  • *****
  • Posts: 7860
  • Portland, Oregon, USA
Re: Pennsylvania A3 Switcher (Kozo)
« Reply #502 on: November 30, 2019, 12:53:00 PM »
Thanks, Roger, Mike, and CNR!

Kim

Offline Kim

  • Global Moderator
  • Full Member
  • *****
  • Posts: 7860
  • Portland, Oregon, USA
Re: Pennsylvania A3 Switcher (Kozo)
« Reply #503 on: November 30, 2019, 01:01:27 PM »
Chapter 5.7– Front Plates

The Front Plates cover the space between the sides of the tank and the horseshoe.  They start along the bottom front of the tank then curve over the top and cover about 3” back along the top of the tank.

These are made from 0.040” sheet brass. After cutting a couple of pieces from the sheet stock, I cleaned up the edges on the mill and took them to the correct width.


The next thing was to shave off 0.040” along the section that would back up to the verge board.  I also cut out a notch for the rim on the verge.  I marked this off and cut the deeper notch on the scroll saw, then filed off the rest.


This how the notch fits.  There will be one of these plates on each side of course.


But, before we can bend them, I need to press mock rivet heads into the side of the plate.  So, I need to make a rivet head puncher.  Here’s what I turned out of W-1 for the punch.


I then made an anvil with a 0.056” hole, as specified by the plans.  I hardened and tempered the punch and anvil, then fit the anvil into a base plate of aluminum that I could hold in my mill vice.  I took a piece of 5/8” square aluminum for a back fence to slide the material along.  The problem was that when I set the fence for the 5/64” distance from the edge (as specified by Kozo in the plans) my punch was too big to fit past the fence.


I’d already hardened the punch, so taking that down more wasn’t an easy option.  The easiest thing to do was make a shorter fence.  So I found a length of 1/4" thick aluminum bar and used that.  No interference there!


I tried punching some test rivets in a piece of scrap (I cut the notch in the wrong place on one plate and had to start over). The challenge here is going to be getting them spaced evenly, and punching them to a uniform depth. The four on the right look pretty good to me. The remaining ones on the left look a little too shallow though.  I need to push a little harder on those, I think.


I’ll practice a little more before I ‘rivet’ all around the front plates.
Kim

Offline mike mott

  • Full Member
  • ****
  • Posts: 418
  • Alberta Canada
Re: Pennsylvania A3 Switcher (Kozo)
« Reply #504 on: November 30, 2019, 03:26:20 PM »
Kim,I found that the easiest way to get the rivets spaced evenly was to make the die underneath the double the diameter of the space + the diameter of the rivet when punched. it might take a couple of tries to get it just right but once set it is pretty consistent. Also I made the die depression to the depth of the head when punched.

Mike
If you can imagine it you can build it

Offline Kim

  • Global Moderator
  • Full Member
  • *****
  • Posts: 7860
  • Portland, Oregon, USA
Re: Pennsylvania A3 Switcher (Kozo)
« Reply #505 on: November 30, 2019, 05:32:57 PM »
Thanks Mike!  That's a great idea.  I'll have to look at doing that.  Not sure how to know how deep to make the hole in the anvil. I'll have to give that a try.  But I can see how to calculate the diameter of the anvil :)

Kim

Offline crueby

  • Full Member
  • *****
  • Posts: 18554
  • Rochester NY
Re: Pennsylvania A3 Switcher (Kozo)
« Reply #506 on: November 30, 2019, 06:45:41 PM »
The way I had gotten the spacings even was to drill a second hole to the side of the one used to make the dimples, that way the previous dimple would have a place to register into, making the rivets an even distance apart.
 :popcorn: :popcorn: :popcorn:

Offline Kim

  • Global Moderator
  • Full Member
  • *****
  • Posts: 7860
  • Portland, Oregon, USA
Re: Pennsylvania A3 Switcher (Kozo)
« Reply #507 on: December 09, 2019, 02:41:36 AM »
Well, if you recall back a few episodes (which I’m sure you don’t, so I’ll tell you) I shaved off a bit of one side of the horseshoe assembly to make it line up better.  Unfortunately, as I suspected, that was only a symptom of the real problem which I hadn’t yet noticed.

It seems that this whole unit is a little cockeyed somehow.  It sits flat, and all the front edges are perpendicular to the base, but the back edge isn’t right.  The backside is all catawampus.  You can see in this picture from above that even though the bottom is nice and square, the top edge has a jaunty angle.  It should, of course, be parallel to the bottom.


I could make up for it with other parts, but I think having the top of the verge board not be square to the rest of the tender will be very noticeable.  I think it will catch everyone's attention. And even if it doesn't, it will bother me.  I won’t be happy.  Plus it will make me care less about the remainder of the build. And I don’t want that.

I don’t know how to get it square at this point. And if I did, I think the ‘fix’ I made earlier will cause yet another problem.  I believe that the reason the front was sticking out, was because the back was whacked out like this.

So, I’ve decided to re-do the whole coal bin unit here. (or Horseshoe assemble as Kozo calls it).

I didn’t have any more 1/4" square brass bar. So while I was waiting for that to come in, I started cutting out the brass plate that will be needed.  The top one is for the ‘vertical board’ (the big piece that wraps around the inside of the horseshoe) and the lower one is the Verge Board (the slopy one that goes around the top of the horseshoe.


Well, this was last week’s update.

During the week my brass arrived.  So, yesterday I started on the lower horseshoe member.  I found a better way to hold it for milling.  And as usual, the 2nd time goes faster:


Here’s a picture of how I lined up the piece so it was parallel to the mill bed.  This works pretty well and is a fairly quick way to get it setup.  Not as fast as the vice, of course, but with such a long piece, the vice was problematic anyway.


Unfortunately, the last step of drilling and tapping the #3-48 mounting holes went terribly awry.  I had gotten some 2.3mm bits off amazon – like a dozen for $3.99 or something.  2.3mm is the recommended drill size to use with the #3-48 roll-form tap.  Unfortunately, the bit I had wasn’t cutting well.  So, I swapped it out.  It took me 3 bits to find one that was sharp enough to cut.  And after drilling the holes, I went to tap them, and the tap almost slides through the hole :(.  I checked the hole size.  2.3mm is about 0.090”.  These holes were over 0.100”!  These supposed 2.3mm drills make 2.5-2.6mm holes.  :(

These are trash bits.  I can’t even really use them for 0.10” bits because they barely cut anyway. And I’m just trying to cut brass!  This isn’t stainless or anything.  Very frustrating.


I’m never buying cheap drill bits again. It isn’t worth it.  Not only do they not work, they ruin the part you’ve put so much time and effort into!

Another lesson learned.  Again… (I think I learned this one already…)

Kim
« Last Edit: December 29, 2019, 05:12:31 PM by Kim »

Offline Steamer5

  • Global Moderator
  • Full Member
  • *****
  • Posts: 1272
  • The "Naki" New Zealand
Re: Pennsylvania A3 Switcher (Kozo)
« Reply #508 on: December 09, 2019, 07:47:44 AM »
Hi Kim,
 Well that’s a bugger on two fronts.

An old friend of mine has a very good saying.......

“The high cost of saving money”

A hard lesson to learn......we’ve all been there done that!

Cheers Kerrin
Get excited and make something!

Offline propforward

  • Full Member
  • ****
  • Posts: 1656
  • MN, USA
Re: Pennsylvania A3 Switcher (Kozo)
« Reply #509 on: December 09, 2019, 02:33:22 PM »
Wow - this is some lovely work Kim - very impressive. So involved! You must be pleased with how this is coming along.

I totally empathize on drill bits. I've made that mistake. At first I assumed I was just drilling holes with poor working practices, but you can't beat quality cutting tools.
Stuart

Forging ahead regardless.

 

SimplePortal 2.3.5 © 2008-2012, SimplePortal