12” gauge DRGW Inspired RR

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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rkcarguy
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Re: 12” gauge DRGW Inspired RR

Post by rkcarguy »

I’m using WP&F’s numbers for the most part, except I am using 1” thick plate blanks for my wheels. I turn a 5/16” wide 1/4” high flange on each wheel, then press them onto the axles such that the flanges measure 12.00” across the pair. Then I spin them between centers and turn a 2-5/6* angle on the tire surface and an 8* angle on the flanges. All work is done with a tool with a 3/32 radius so the root of the flange has this radius. The reason for this is that once you cut the angles on the flanges with a flange radius you are trying to measure a point floating in space. Secondly, doing the cleanup cut after pressing allows me to true each wheel set perfectly if they don’t press on exactly true.
Lastly, I run a .400” or 10mm distance between any guard rails. This assures that if the gage opens up to the maximum somewhere and worn flanges allow more side to side play, that one flange won’t strike the guard rail. I drew this all in CAD to make sure it was going to work before I committed and turned my first 4 wheel sets. Any extra width to the wheel blank simply becomes more tire width.
rkcarguy
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Re: 12” gauge DRGW Inspired RR

Post by rkcarguy »

To add to the above, I am using 12-1/8 for my gage, 12-1/4” maximum between the rails. Using the groovy track method so movement isn’t really an issue. With all the above, the riding car traverses the curve of my turnout 40’ radius very nicely and stays centered between the rails, the flange angles don’t even touch and a dykem test shows the contact area almost centered on the railhead and wheels tire surface.
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Re: 12” gauge DRGW Inspired RR

Post by 0351 »

I like the thought of one day picking up an Ottaway steamer, and would like to stay within a gauge tolerance that will accommodate the STR Ottaway.
I’m currently looking to get some quotes on have axles machined from 4140 steel.
Starting to look like I will have more money invested in 16 axles, than I have invested in my wheels.
Unfortunately, when designing my sideframes, the bolt hole spacing for the flange bearings were cut to 1.25” flange specifications. In reality, the holes should have been spaced for a 1” flange bearing, so the bearings could be pressed onto the axles.
Considering a bushing/spacer to go between the outside of the wheel and the flange bearings to keep the axles from possible slipping.
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rkcarguy
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Re: 12” gauge DRGW Inspired RR

Post by rkcarguy »

Curtis, the inner races of the flange bearings have set screws in them. Drill some dimples in the axles and set them with loctite they aren’t going to go anywhere. I used stressproof steel for my axles, it’s a medium carbon material with a good balance of strength and workability. 4140 is not needed and will cost a 2nd mortgage, when I bought mine it was less than $100 for 20’ and it comes sized for a nice slip fit through the bearings with no machining.
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Harold_V
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Re: 12” gauge DRGW Inspired RR

Post by Harold_V »

I heartily endorse the idea of using Streeproof in lieu of chrome moly, especially if the cost is lower. Both choices are quite acceptable, however, as would be the use of 1042/1045 polished shafting. Of the three, Stressproof offers the best machinability, yielding clean, untorn cuts.

H
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0351
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Re: 12” gauge DRGW Inspired RR

Post by 0351 »

I will say, I’m not up to speed on the different metal specs. I’ve been talking with Jim of L&B Trains in Illinois regarding machining axles.
He is saying to use 4140 steel. At the moment it is costly at $45 per axle just for the material. Still waiting to hear back on labor cost. He figured there would be a couple hours per axle.

Ryan, you feel good about set screws holding with lateral thrust?

Here on the farm, I have 40 1” pillow block bearings in use on the barn fans, with no set screw issues, however there is also no lateral loading.

At the moment I am making up some “poor-man” so I can keep the project “rolling”.
I took some 1.25” keyed shafting, and some 1.25 coupler sleeves cut down to 11.25”.
Theses will be slipped onto the shafting to create Shoulders to hold them wheel gauge. Once the wheels are in place, the coupler sleeve can be welded to the wheels without damaging the bore, and axle.
Unorthodox,yes. Hopefully that will allow me to get a set of trucks assembled, and keep working until I can get some legit axles machined.
Last edited by 0351 on Thu Jul 14, 2022 7:31 am, edited 3 times in total.
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Harold_V
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Re: 12” gauge DRGW Inspired RR

Post by Harold_V »

0351 wrote: Wed Jul 13, 2022 11:36 pm He is saying to use 4140 steel.
I'm not suggesting it's a bad choice, it isn't. However, it's hugely overkill for a project like this. That's why I made mention of plain old medium carbon steel------such as C1045. Even without being ground and polished, it will work just fine, assuming the individual who does the machining has a clue about concentricity and is adept at achieving proper fits.

Before you jump in, assuming you're price conscious, I'd suggest you make a few inquiries for the mentioned options. Truth is, once made, you won't know the difference, as all three mentioned are well within the requirements for those axles. All should be avoided if any welding will be required, however.

H
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Erskine Tramway
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Re: 12” gauge DRGW Inspired RR

Post by Erskine Tramway »

While this is a 7-1/2" gauge engine, this is how I'm doing the axles. The wheels I have are bored 1", with a keyway, so I made the main axles out of 1" keyway stock. To set the gauge, I cut pieces of 1" ID tubing to make my back-to-back 7-1/8". My axles extend quite a ways past the wheels to the take-up bearings I use. So, I cut more of the tubing as long spacers to keep the wheels centered. The spacers butt up against the inner races of the bearings. They also add a little bending strength to the axles. Here's a picture, before I cut the outer spacers.

Mike
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0351
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Re: 12” gauge DRGW Inspired RR

Post by 0351 »

Erskine Tramway wrote: Thu Jul 14, 2022 9:40 am While this is a 7-1/2" gauge engine, this is how I'm doing the axles. The wheels I have are bored 1", with a keyway, so I made the main axles out of 1" keyway stock. To set the gauge, I cut pieces of 1" ID tubing to make my back-to-back 7-1/8". My axles extend quite a ways past the wheels to the take-up bearings I use. So, I cut more of the tubing as long spacers to keep the wheels centered. The spacers butt up against the inner races of the bearings. They also add a little bending strength to the axles. Here's a picture, before I cut the outer spacers.

Mike
Mike thanks for sharing!
This is roughly the same idea I’m going to use for stand in axles. Doing so will allow me to get the truck bolster length figured out and truck assembled.
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rkcarguy
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Re: 12” gauge DRGW Inspired RR

Post by rkcarguy »

Your take up bearings should have specs available for thrust loads, I believe it’s typically around 20% of the load rating. We have some fairly large flange bearings in our rotoblaster that endure side loads just fine, it’s just important that you transfer punch the set screw holes and drill dimples in the axles for them to lock into and nothing is going to move. Combine that with Erkshines pipe spacer method and I think you’re good.
Glenn Brooks
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Re: 12” gauge DRGW Inspired RR

Post by Glenn Brooks »

0351 wrote: Sun Jul 10, 2022 10:33 pm All valid points. So, in staying with 12” gauge,
I am aware of the IBLS wheel/track gauge standards for 3” scale. Curious as to what your thoughts on the wheel sets B-T-B, and track gauge. Seems it’s anywhere from 12”-12.25” on gauge. My wheels are 3” scale, designed for 12lb rail.

Glenn what is your back to back, and actual track gauge?

Northview & Frisco is using a 11.25” b-t-b, and a 12”—12.125” track gauge.

WP&F is using a 11.375” b-t-b, and a 12.25” track gauge.

I know James has ran his 11.25” b-t-b on WP&F’s 12.25” gauge track without any big issues.

351,

My backyard track is set to 12” gauge on tangents and up to 12.250 on the sharper curves (35’- 40’ radius). 12.125” of curves over 50’ r.

My Back to back is somewhere between 11.0” to 11.250”. Ottaway and several other unknown truck makers allowed very generous clearances up to 1/8” per side between the rail head and the flange root on my wheel/axle sets - as a result, my trucks all have different flange widths and different back to back measurements. It depends on the overall width of your flanges- including the root radius.

Generally, 3” scale flange width is mostly around 3/8” wide at the root. Flange Radius at the root, varies from .157” up to 1/4” in different wheel geom drawings. And in practise, I have measured wheel geometry all over the board, some as skinny as .300” flange width width in some old, turn of the century wheel sets(1900 or prior). I believe partly this is a product of nonstandard wheel construction, and partly a result of 100 years of inconsistent wear on individual wheel sets. Overall, I think the 3” IBLS wheel standard is OK, except for their root radius - .157” radius is ridiculously outside the envelope of 12# rail geometry. I have no idea what rail they were thinking about when they published this dimension.

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

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rkcarguy
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Re: 12” gauge DRGW Inspired RR

Post by rkcarguy »

I ended up drawing a section of a wheel set on the rails to see where the contact patch ended up and how it centers. Things change a lot with small changes to the radiuses and angles . The flange root radius is generally equal or larger to the radius on the rail head. As the wheel set moves side to side the flange root radius combined with the wheel taper helps it self center. If the railhead is too sharp it will obviously chew up the flange roof radius on the wheel. I get the rounded flat bar for my rails and it seems to have a 1/16” radius so I went with a 3/32” flange root radius.
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