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

Post by little giant » Tue May 19, 2020 4:05 am

There are illustrations of this type of valve in the locomotive encyclopedia. Thanks for making them easier to help me understand how to make them.

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

Post by thunderskunk » Tue May 19, 2020 5:24 am

I think I’ve crossed paths with your build thread a few times here; that’s one sharp looking engine! Great choice and fine modeling.
"We'll cross that bridge once we realize nobody ever built one."

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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 May 19, 2020 10:26 am

Robert:
I've had to get my nerves up to this task. Most of the visible details will be sculptures, not fixture machined parts.
I've got two of the sand-trap domes finished, and two more to go. Slow tiny work, and hard to hold. I'll continue those today.
For rounding and blending those cast curves, my debarring wheel setup has been invaluable. That and hand files!
Deburring Wheel sml.jpg
Next pic shows the setup for cutting the sand-trap dome to the required 20 degree angle. The first completed mini-dome is in the foreground.
The silver-brazed bar+rods discussed in the previous post cleaned up nicely and is the source material to make the domes.
Leaving it as a long stick provides a way to hold it for sculpting and machining.
Sander build 6 sml.jpg
The magnetic digital protractor is invaluable. I originally got it for adjusting the side wheel carriers on the Seattle Center Monorail trains!
With 48 side wheels per 4-car train that was a difficult task. It became simple with the didi-protractor. Stick it onto the carrier and adjust one bolt until the correct angle reading was achieve. Then move onward 47 more times...

Robert: I thank you again for your invaluable prototype photographs! Much appreciated.
To be continued.
RussN
Last edited by NP317 on Tue May 19, 2020 10:43 am, edited 2 times in total.

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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 May 19, 2020 10:40 am

thunderskunk:
Thanks for your compliments. It's been an enlightening project.

little giant:
I am pleased you can get some ideas from my posts. That's what this community is all about.
Too bad I could not get these printed or cast. There are obviously other people who would like to get them too.

When I get these finished I expect Jack Bodermann to pipe up and say:
"Oh. I've got those castings How many do you want?"

Hahaha.
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 May 19, 2020 9:32 pm

I got more Shop time today. It was grey and rainy all day long, but who cares when we can be creating in our Shops!

I got three more tasks accomplished:
The final 2 sand-trap domes;
The 4 air input pipes;
And the 8 square-drive plugs, two per valve assembly.

The final two sand trap domes were sculpted as previously described. Again, the deburring wheel was key to blending the curves.

Air input pipes (1/8-MPT):
First I mounted the main valve bodies in the mill vice, indexed for easy exchange of the bodies. I marked the bodies where the hole needed to be drilled, to make sure I didn't screw up as I sometime do...
I needed to drill a hole obliquely through the bottom curved surface. I ended up using a 1/8" diameter ball end mill, and it worked perfectly.
No picture so you get to use your internal vision.

The pipe that fits in the valve body is 1/8" diameter brass solid rod (non-operating valves. Remember?)
Pic shows the 1/2" long "pipes" threaded on one end for the union. The other end presses/glues into the valve body. The rod stock I used is also seen.
Sander build 8 sml.jpg
Lastly, the square drive plugs: 8 each, 3/16 MPT.
First pic is threading the plugs. Then that part was hack-sawed off the rod in the collet.
Sander build 7 sml.jpg
Then I made a threaded "socket" holder from 1/2" diameter brass rod, and mounted it in a 4-sided collet block to use in the mill to cut the square drive ends.
These parts are quite short so I used needle-nosed pliers to thread them into the holder for milling, and removal after milling.
Pic shows the set up for milling the square drive ends.
Sander build 9 sml.jpg
A little deburring and they fit right into the MPT threaded valve bodies.
Sander build 10 sml.jpg
Still to do is solder the little domes on to the valve bodies., and add their 0-90 bolts for looks.
I will need to drill indexing holes to hold the parts in register during soldering. I'm still cogitating how best to do that.
Getting closer.
RussN

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

Post by ccvstmr » Wed May 20, 2020 10:30 am

Russ...did you ever realize, that sometimes the smallest parts take the longest time to fabricate? Will add, machines sometimes have a bad habit of grabbing those parts and flinging them off to the dark corners of your shop...NEVER to be seen again!

Nice job on the sander valves. Just one more way to kick things up a notch for your loco! Please keep posting your other detail efforts. Carl B.
Life is like a sewer...what you get out of it depends on what you put into it!
I don't walk on water...I just learned where some of the stepping stones are!
I love mankind...it's some of the people I can't stand!

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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 » Wed May 20, 2020 1:54 pm

Carl:
Indeed those small items are the most difficult to make! And find, sometimes...
This morning I located a dropped part in the cuff of my jeans! Whew!

I'm taking a lunch break from working on those sander valves.
There will be several more postings before they are completed and installed.
Just to keep you bored...

If a reader learns even one useful thing from my ramblings it will have all been worthwhile.
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 » Wed May 20, 2020 9:12 pm

More progress on the Sander Valves:

I got all the parts completed and shown below:
Sander build 11 sml.jpg
Next I decided how to use a 1/16 dia. brass pin to index the valve domes while soldering them to the bodies.
Some careful layout and drilling and the next step was obvious.
Sander build 12 sml.jpg
I used this solder powder + flux, the same I used to solder the tender half-round brass onto the top if the body:
Sander build 13 sml.jpg
You can see the grey paste on the small screw driver at the bottom of the container.

Cleaned and assembled the parts with the solder paste, and applied my MAP torch for about 10 seconds each, and DONE.
After cleaning the parts here they are, ready for assembly of all those other little pieces:
Sander build 14 sml.jpg
After final assembly, here are the four sander valves, ready for final cleaning and painting:
Sander build 15 sml.jpg
The black paint is drying as I type this update.

Next: Installation and plumbing. Moving steadily along.
RussN

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

Post by Greg_Lewis » Fri May 22, 2020 6:45 pm

Thanks, Russ, for this. I need two of those valves, so you've saved me a lot of cogitating.
Greg Lewis, Prop.
Eyeball Engineering — Home of the dull toolbit.
Our motto: "That looks about right."
Celebrating 30 years of turning perfectly good metal into bits of useless scrap.

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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 » Fri May 22, 2020 7:18 pm

Glad my postings can be of use to someone.
I still wish someone would make CAD drawings so these can be printed and/or cast.
RussN

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

Post by Berkman » Fri May 22, 2020 9:40 pm

Russ have you talked to Eccentric Engineer, Brian Keim or Mike Venezia to see if they might be interested? I feel like these sanders would fit well into any of their part catalogs.

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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 » Sat May 23, 2020 10:40 am

Berkman wrote:
Fri May 22, 2020 9:40 pm
Russ have you talked to Eccentric Engineer, Brian Keim or Mike Venezia to see if they might be interested? I feel like these sanders would fit well into any of their part catalogs.
No, I have not. But I also figured they would see my construction series and come to that conclusion on their own.
Hopefully.

I know that Brian Keim sells really gorgeous castings for a different operating sander valve in 1.6" scale. I purchased them, but they were not correct for my Mikado.
So they are sold to others who wanted them.
We'll see where this subject goes.
RussN

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