3/4-inch scale B&O P7d Cincinnatian

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Bill Shields
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Re: 3/4-inch scale B&O P7d Cincinnatian

Post by Bill Shields »

Yes they are. Right smack off the steam feed pipe where it connects to the cylinder casting there is a boss.

From there the pipe goes straight cup and the snifter is just above the running board.
Too many things going on to bother listing them.
Andypullen
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Re: 3/4-inch scale B&O P7d Cincinnatian

Post by Andypullen »

Berkman wrote: Sat Apr 02, 2022 1:25 pm are they there?
The President Washington at the B&O museum has Viloco drifting valves. They aren’t on the photo though.

Andy Pullen
Clausing 10x24, Sheldon 12" shaper, ProtoTrak AGE-2 control cnc on a BP clone, Reed Prentice 14" x 30", Sanford MG 610 surface grinder, Kalamazoo 610 bandsaw, Hardinge HSL speed lathe, Hardinge HC chucker, Kearney and Trecker #2K plain horizontal mill, Haas TL-1 lathe.
Andy R
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trailing truck

Post by Andy R »

The bearings have been finished and the springs installed on the trailing truck:
trailing truck.JPG
timken bearing cap.JPG
Once the pivot bolt and spherical washers are made and installed, the main springs will be installed.
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JBodenmann
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Re: 3/4-inch scale B&O P7d Cincinnatian

Post by JBodenmann »

Hello My Friends
Very cool Andy. The Timken axle box covers are a nice detail.
Jack
Andy R
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Timken axle box covers

Post by Andy R »

Thanks Jack!
I have another dozen of the Timken axle box covers that are for the tender trucks.
They really are a nice detail.
Regards,
Andy
Andy R
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finishing the springs for B&O P7d Cincinnatian

Post by Andy R »

IMG_4276s.jpg
OK, so making a bolt isn't so interesting.
It's for the trailing truck to rear frame extension connection.
The domed washer fits in a similarly dished recess in the rear frame extension and the Delrin washer fits between the rear frame extension and the trailing truck in another suitably-sized seat.
The bolt as shown on Mr. Coventry's 1930 and 1959 drawings match, but is about 5/8 inch too long, so it was made shorter, of course.
Making the custom bolt allowed connecting the rear truck equalizers with the equalizer hangers, yoke, etc., and then completing the installation of all of the remaining spring assemblies on the main frame.
Here is a picture of the connection:
IMG_4277s.jpg
Once all of the springs were done it was assumed that assembly of the brake hangers to the frame and brake rigging would be simple, but alas! Several mistakes were found in work that was fabricated a long time ago.
I met some live steamer friends yesterday for lunch and took the assembled frame for post-lunch show-and-tell, and their consultation is duly appreciated. I'm now working on the fixes that they suggested, which will be reported later.
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Bill Shields
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Re: 3/4-inch scale B&O P7d Cincinnatian

Post by Bill Shields »

better too long than too short !
Too many things going on to bother listing them.
Andy R
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Brake Rigging Assembly Dwg 167 (and 703)

Post by Andy R »

Second try on this - in more ways than one. The internet disconnected after trying to post on this.

I found that the brake beams were made too long, by 3/32-in. A dimension on the drawings made mis-reading a possibility. The brake beams were duly mounted and the shoulders reduced - between centers. I only ruined two. Luckily I had a full set of spares.

The hanger brackets for the aft brake shoes were also wrong - too tight to the frame. The drawings dimensioned to the centerline of a slot - so the error was the width of the slot - 1/4 inch. The hanger brackets are part of the rear cradle, (Drawing 138) so the frame was disassembled to allow mounting the cradle in the mill and enlarging the slots. I also made spacers to accommodate the now wider slots.

After reassembly of the frame, here's the successful reassembly of the brake rigging at the front axle:
IMG_4295s.jpg
Here's a view at the main driver axle:
IMG_4296s.jpg
Here's a view at the rear saddle extension (the spacer is not really visible):
IMG_4297s.jpg
And this is looking down where the connection to the brake fulcrum is mounted:
IMG_4298s.jpg
All fasteners are temporary of course, because the hangers will have to be removed in order to mount the drivers.
Next up are the driver pins.
jcbrock
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Re: 3/4-inch scale B&O P7d Cincinnatian

Post by jcbrock »

Beautiful work Andy. All that slotting, probably one of my least favorite activities!
John Brock
Andy R
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Crank Pins for 3/4-inch scale B&O P7d Cincinnatian

Post by Andy R »

Thanks for the compliment JC !

I took a day off work last week and used that time to turn the crank pins (main pins part No. 2141; front pins No. 3141, and rear pins part No. 4141). The Drawing No. 132B dated Dec. 20, 1929, shows the front and rear drivers bored 3/8 inch for the drive pins. But the original builder bored these 1/2 inch - the same as the main drivers, so I redesigned the front pins no. 3141, and rear pins part No. 4141 to accommodate the different diameters. I then installed the pins in the drivers using Loctite. The attached photo shows one of the main drivers part No. 2132, and one of the driven drivers, part No. 1132 with the pins installed.

I also made the rod retainers, parts no. 5141 and 6141. Instead of boring the drive pins to accommodate a flathead screw for the retainers, I bored them to accommodate #5 Allen screws.
IMG_4305s.jpg
Comparing the 1929 drawing with the driver castings, there is one fewer spoke in the castings. Mr. Coventry, in his articles in the ModelMaker magazine indicated that he made the patterns for the drivers, so I'm not changing a thing.
Andy R
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Axles for 3/4-inch scale B&O P7d Cincinnatian

Post by Andy R »

Axles were test fitted in order to check the centerline differences. That will allow starting work on the rods.

I had anticipated measuring the out-to out distance and subtracting the rod diameter (at the wheel) to get the centerline spacing but re-discovered a gap in my measuring capability. I have 0 to 1 inch, 1 to 2 inch, 2 to 3 inch, and 3 to 4 inch micrometers. And I have a Starrett No. 224 set with 6 to 12 inch capacity. But I have no micrometer in the 4 to 6 inch range.

So I started the check with the most rudimentary tool, a scale with 1/64 inch graduations, then used a “6-inch” vernier which has enough capacity, and measured all axles to be exactly the same 5.25-inch centerline spacing. That is close enough to accommodate an eccentric bronze or brass bush in one end of each rod, if needed. Now to make necessary jigs for machining the rods.
IMG_4306s.jpg
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JBodenmann
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Re: 3/4-inch scale B&O P7d Cincinnatian

Post by JBodenmann »

Lookin' good Andy!
Jack
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