12" gage truck sides

Discuss park gauge trains and large scale miniature railways having track gauges from 8" to 24" gauge and designed at scales of 2" to the foot or greater - whether modeled for personal use, or purpose built for amusement park operation or private railroading.

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Glenn Brooks
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Re: 12" gage truck sides

Post by Glenn Brooks » Wed Dec 20, 2017 12:39 am

Ryan, how many springs do you plan on using each side? Iam thinking maybe 2 or three on each side for the riding cars. Might be effective to cut thin sections of pipe and spot weld them in place to seat the springs. Something similar to this:
7FD5CBE0-5098-4A93-AD10-88113FF78128.jpeg
Glenn
Moderator - Grand Scale Forum

Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge

Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....

rkcarguy
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Re: 12" gage truck sides

Post by rkcarguy » Wed Dec 20, 2017 11:15 am

The perch is just a touch over 2" wide, so if you went with 5/8" diameter springs you could fit three, 3/4" or 1" diameter would fit two per side.
I know in my machine shop days we used some 5/8" diameter springs on some of the smaller dies we built.

rkcarguy
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Re: 12" gage truck sides

Post by rkcarguy » Wed Dec 20, 2017 11:17 am

Looking at your picture, using some proper size freeze plugs might be the answer.

0351
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Re: 12" gage truck sides

Post by 0351 » Thu Dec 21, 2017 12:23 am

rkcarguy,
Long time lurker as I've been following your post comtiplating building my own 11.25" railroad. Thought you might be interested is these photos of trucks similar to your design. Not mine, came across them while searching for homemade trucks.
Attachments
IMG_2766.JPG
IMG_2767.JPG
IMG_2768.JPG
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Glenn Brooks
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Re: 12" gage truck sides

Post by Glenn Brooks » Thu Dec 21, 2017 11:35 am

Cool looking trucks. Very interesting design of the bolster. Looks very functional. Thanks for posting.

As an aside, welcome to the Forum! Don’t hesitate to post any questions you may have regarding building your proposed RR. Lots of expertise on the board.

Regards
Glenn
Moderator - Grand Scale Forum

Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge

Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....

rkcarguy
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Re: 12" gage truck sides

Post by rkcarguy » Thu Dec 21, 2017 1:56 pm

Glenn, I'm thinking I'd weld some slices of pipe(like a cam lobe) to the top of the bolsters on the heavy duty versions, and either leave the pivot bolt loose, or run spherical bearings at the pivot points, so the trucks can *freely* pivot front to back independent of the springs, but not side-to-side. The frame would then need bars on each side of the pivot for these "cams" to slide on as the trucks pivot on the frame.
For my riding car, I'm planning to use fairly soft springs and it will not see much variance in load, so I don't feel this is necessary.
Even with the design above, there is resistance from the springs to the truck pivoting back and forth, and with super stiff springs the truck may lift a wheel when the track changes grade, or for instance, one is loading/unloading a piece of rolling stock from a pickup.

rkcarguy
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Re: 12" gage truck sides

Post by rkcarguy » Fri Dec 22, 2017 1:03 am

I'd love some feedback on this, if what I'm talking about makes sense? I think it does.
Looking at the *above* truck, it has that large pivot surface that will force the bolster to remain flat to the frame of the piece of rolling stock. So lets say you had a big dip in the track, the springs in the truck would have to compress to allow it to keep all four wheels on the track. The stiffer the springs the more apt it's going to be to lift the front wheels as the car moves into the dip.
At the same time, the loading of the truck is transferred clear into the center of the of the bolster, requiring it to be heavier due to the leverage placed upon it.
The picture below shows a bolster, and you can see the slide bearings are located out closer to the wheels which transfers the load to the frame. My thought is to round these and run a spherical bearing in the pivot point to allow the truck to tip front to back, but not side to side, completely independent from the movement offered by the springs. This should mean even wheel loading and complete conformance to the track, even with the stiffest springs and the car empty.
bolster1.jpg

rkcarguy
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Re: 12" gage truck sides

Post by rkcarguy » Wed Jan 03, 2018 1:00 pm

The first set of truck parts is due to arrive tomorrow from the laser cutter:)

rkcarguy
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Re: 12" gage truck sides

Post by rkcarguy » Mon Jan 08, 2018 3:55 pm

lasertrucksides.jpg
Here they are. The little holes in the U-shaped plates are for 1/4-28 grease fittings, I'll be grinding grooves in the back of the "slide plates" so the grease will flow throughout the sides of both plates.

rkcarguy
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Re: 12" gage truck sides

Post by rkcarguy » Tue Jan 09, 2018 12:58 am

truck1.1.jpg
truck1.2.jpg
trucktap.jpg
trucktapped.jpg
This worked out pretty well, I easily ream drilled the laser-cut grease fitting holes out to 7/32 with my cordless drill, and then tapped them 1/4-28.
I don't have any 1x2 flat bar or tube on hand at the moment, so this is the best I can do to show how it goes together, sans rectangle tube.

rkcarguy
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Re: 12" gage truck sides

Post by rkcarguy » Tue Jan 09, 2018 1:25 am

By the way, those are old valve springs from an early 80's Volvo motor, should be good for my riding car at around 80#'s each spring x 8.

Pontiacguy1
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Re: 12" gage truck sides

Post by Pontiacguy1 » Tue Jan 09, 2018 12:40 pm

They look pretty durable. The bearings you have are WAY overkill for the load and speeds you will be seeing, so they should last a long time. Most bearings like that will fail because the seals fail. Once the seals start letting dirt in and grease out, then they are done. Don't over-grease them either. The bearings should come from the factory filled 75% with grease. I've seen people pump new bearings full of grease until it starts to purge out from under the seals. This only will damage the seals, possibly causing them to pop out! A shot of grease once per year should be more than enough to keep them well lubed.

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