90-Ton 2-8-2 Build, 1.5"/ft. Scale, 7.5" Gauge

Where users can chronicle their builds. Start one thread and continue to add on to it.

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Dick_Morris
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Re: 90-Ton 2-8-2 Build, 1.5"/ft. Scale, 7.5" Gauge

Post by Dick_Morris » Sat Jan 20, 2018 4:58 am

Nice work on the backhead (and the rest of the locomotive). The acorn nuts do a good job of simulating the flexible stay caps.

Asteamhead
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Re: 90-Ton 2-8-2 Build, 1.5"/ft. Scale, 7.5" Gauge

Post by Asteamhead » Sat Jan 20, 2018 6:22 am

Little giant,
You may see the answer by studying that very old drawing. Should be about 1/10 " which will do for a sufficient steam pass.

Russ,
No hurry! Please have a look on that ancient drawings out of a time when ball cooks weren't available to us steamers. The cover plate is to be seen at the top of page 1. You may use that device on top of the main steam outlet (without that throttle), if it's mounted the same way, of course.
If anyone intends to built a valve throttle of his own, he's welcome to use my sketches!
The "Wagner" prototype had been standard here for nearly all Pruissen, DR and DB locomotives. That model valve worked for thousands of hours and can be handled by a finger tip :D

Asteamhead
Attachments
Throttle 44 with cover plate (1).png
Cross section through valve body with cover plate.
Throttle 44 (valve parts 2).png
Valve parts just to your information
Throttle 44 lever  parts (3).png
Valve leverage just to your information
44 cab with main throttle lever 027 red.jpg
View into the 44's cab with the throttle opened half

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makinsmoke
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Re: 90-Ton 2-8-2 Build, 1.5"/ft. Scale, 7.5" Gauge

Post by makinsmoke » Sat Jan 20, 2018 9:49 am

That's very ingenious!

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NP317
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Location: Northern Oregon

Re: 90-Ton 2-8-2 Build, 1.5"/ft. Scale, 7.5" Gauge

Post by NP317 » Sat Jan 20, 2018 11:42 am

nabob wrote:
Sat Jan 20, 2018 1:21 am
IIRC the crown sheet plaque was listed in the Little Engines catalog. I really looks good and is helpful as well. nabob
Thanks for that recollection. Hope it's true. I was unable to locate that plaque in the Little Engines on-line catalog this morning.
'Doesn't mean its not there...

Asteamhead:
After further consideration (and my morning cup-o-coffee) I understand your steam dome water ejector system.
A good example of simple engineering at its best, and definitely worth considering as a solution to potential priming into the cylinders.
Thanks again.
~RussN

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NP317
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Re: 90-Ton 2-8-2 Build, 1.5"/ft. Scale, 7.5" Gauge

Post by NP317 » Tue Feb 06, 2018 6:11 pm

Time for some more.
- Detailed side sheets for the power firebox covers.
- Some discussion of riveting
- Whatever else spills from my keyboard.

First a picture of the finished detailed backhead, with the Trycock drain sculpture in place:
Backhead+H2O) Drain sml.jpg
Next: Begin making the detailed side and throat sheet covers.
And here is the bare lower firebox demanding to be covered with details:
1-FB Sheets Bare sml.jpg
First task was to make cardboard patterns, followed by the sheet metal pieces. I used the same steel sheet used for the jacketing.
2-SideSheet Pieces sml.jpg
Then test fit the bare pieces:
3-SideSheetBare Testfit sml.jpg
More next posting.
~RN
Attachments
1-FB Sheets Bare sml.jpg

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NP317
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Re: 90-Ton 2-8-2 Build, 1.5"/ft. Scale, 7.5" Gauge

Post by NP317 » Tue Feb 06, 2018 6:41 pm

More:
Sorry about the repeat picture above, but I'm unable to get rid of it! 'Been having trouble getting the picture selection/download/replacement working properly. Hmmm.

So, continuing on, next task was to mark all the holes for drilling the 1/8" rivet holes and the #4 screw clearance holes for the flex-caps.
I used the mill with DRO and a small center drill to mark the hole locations, properly supporting the sheets underneath with parallels.
4-Spotting Rivet Holes sml.jpg
The lots of drilling using the drill press while hand holding the deburred sheets With Gloves! Then deburring all those holes and here's the result:
5-SideSheet Drilled sml.jpg
Next: Rivetting.
I used 1/8" diameter round-head copper rivets. First insert into the sheet holes, then cut them off, and finally WHACK! the back stub to set them.
Here's the nearly-flush cutter at work:
6-Rivet Cutting sml.jpg
And the resulting trimmed end (left side) and peened over (right side):
7-Rivet Length sml.jpg
I made a round-head form tool (used a ball-nosed cutter in the mill) which stayed in the vice, leaving me two hands available to do the peening. 4 light hammer whacks were sufficient.
8-Rivet Form sml.jpg
Some notes on the riveting:
-Too much peening would deform the sheet metal, so I trimmed the rivets short to allow low-pressure peening of the trimmed end.
-The form tool has the depression off center (look closely at the picture) allowing positioning that did not interfere with rivets already in place.
-When installing a row of rivets, be sure to start at either end, then the middle, then keep "splitting the difference" until the row is filled. This prevents "creep" from further deforming the sheet metal.

More next post.
~RN

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NP317
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Location: Northern Oregon

Re: 90-Ton 2-8-2 Build, 1.5"/ft. Scale, 7.5" Gauge

Post by NP317 » Tue Feb 06, 2018 6:53 pm

Continuing on:
Here are the riveted side sheets ready to fitting. One shows the peened side; the others the visible side.
9-SideSheets Riveted sml.jpg
Then fitting on the boiler and planning the mounting holes (pop-rivets & bolts):
10-SideSheets Testfit1 sml.jpg
11-SideSheets Testfit2 sml.jpg
Finally, they all got painted and the assembly process begins. Note the bare unfinished triangle above the corners.
13-SideSheets Painted1 sml.jpg
Finally, fabrication and painting of the "corner jacket" pieces was done:
14-Corner Jackets sml.jpg
All three sheets were held in place by just 2 small bolts at the upper rear, and 4 pop-rivets at the corners.
The throat sheet is primarily held by "capture" between the lower frame and the upper jacket, plus the 4 end pop rivets.
Pretty simple!

Final results on the next post.
~RN
Last edited by NP317 on Tue Feb 06, 2018 7:09 pm, edited 1 time in total.

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NP317
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Location: Northern Oregon

Re: 90-Ton 2-8-2 Build, 1.5"/ft. Scale, 7.5" Gauge

Post by NP317 » Tue Feb 06, 2018 7:00 pm

And here are the finished results:
15-SideSheets Done1 sml.jpg
16-SideSheets Done2 sml.jpg
17-SideSheets Done3.jpg
I hope this documentation spurs other on to pursue similar details. As you have seen, it's not really that difficult.
Having good prototype photos to copy, and the patience to perform the multitude of repetitive steps, are primary requirements.
I think the results speak for themselves. The model locomotive looks much more realistic than before I started making these 4 cover sheets.
Now on to the plumbing! I'm FINALLY getting closer to steam tests.

Questions? Ask away.
And don't fear similar tasks with your own projects.
~Russ N.

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NP317
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Location: Northern Oregon

Re: 90-Ton 2-8-2 Build, 1.5"/ft. Scale, 7.5" Gauge

Post by NP317 » Tue Feb 06, 2018 7:23 pm

Correction:
The copper rivets used are 3/32" shaft diameter, not 1/8".
More scale appearance that way.
~RussN

flyguy
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Re: 90-Ton 2-8-2 Build, 1.5"/ft. Scale, 7.5" Gauge

Post by flyguy » Wed Feb 07, 2018 1:22 pm

Your work is beautiful. I hope to do much of the same on my Allen Ten Wheeler I am finishing up. I don't think I ill have the clearance between the drivers and the firebox to do the boiler rivet details, but I do plan to do the back head similar to yours. One of the things I do not like about the stock Allen locomotives is the reverser quadrant. I like the look of the quadrant on your locomotive. Is this a railroad warehouse part? Any idea if it would still be possible to get the part from them?

Thanks for all the posts,

James

Berkman
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Re: 90-Ton 2-8-2 Build, 1.5"/ft. Scale, 7.5" Gauge

Post by Berkman » Wed Feb 07, 2018 1:29 pm

Curious how the trailing truck pivots? Looks like it has less travel or flexibility than say a delta. Just curious

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NP317
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Location: Northern Oregon

Re: 90-Ton 2-8-2 Build, 1.5"/ft. Scale, 7.5" Gauge

Post by NP317 » Wed Feb 07, 2018 3:21 pm

Flyby: Thanks.
My Allen Ten Wheeler does not need the side-sheet details, because the rear driver and aft plumbing pretty much covers everything.
The backhead however could use a detailed cover. Go for it and share your work here!

The reverse quadrant on my Mikado is not commercially available. I fabricated it to follow the prototype as closely as I could.
As a result, it looks more "delicate" due to its small (but scaled) size. Built from steel (except for the cast brass lock handle), it is plenty strong. Copy away.
J-Bar 1.jpg
Rayonier #90 2007 015.jpg
The handle came from RR Warehouse, now closed. I don't know who bought the patterns, but SOMEONE must be making them available!
Try Little Engines first. Mike has really been accelerating his offerings. Thanks Mike.

Berkman:
The trailing truck has plenty of side swing from hanging brackets to the axle+bearing boxes+radius link assembly.
Below is a picture of the exploded parts, prior to assembly. It may make sense with some study. Otherwise I can take some more pictures for you.
I made one change from the single radius link arm to a double almost-parallel set of arms. This allows more side motion without binding the axle boxes in the frame, while giving a motion radius more appropriate for the locomotive.
~RussN
2-8-2 Rear Truck 11-2012.JPG

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