12" working railroad

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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Topics may include: antique park gauge train restoration, preservation, and history; building new grand scale equipment from scratch; large scale miniature railway construction, maintenance, and safe operation; fallen flags; track, gauge, and equipment standards; grand scale vendor offerings; and, compiling an on-line motive power roster.
rkcarguy
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Re: 12" working railroad

Post by rkcarguy » Fri Oct 19, 2018 10:32 pm

I got the springs installed. I was trying to figure out a way I could install them and then bolt in the retainers. What I came up with was I found some 1/4" coupler nuts that fit inside the springs with just a little clearance on the inside diameter yet short enough so the spring coil binds before the nuts would bottom out inside it. So I put one inside each spring, slipped it into place with a washer all clamped down with the channel locks, and then inserted the allen screw from the bottom while grabbing the coupler nut with some tiny pliers between the spring coils. These springs are 135# x 8, so just over 1000# max gross weight capacity for the riding car.

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steamin10
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Re: 12" working railroad

Post by steamin10 » Sat Oct 20, 2018 8:13 pm

Nah! Wheels are wheels and are basic turning no matter the size. With cast iron skins or flame cut oxides it is all the same to get into good metal and not destroy the tool. If you are smart you will use the tail stock to reference the working tool and touch in for setting the handwheel. Then as you change form rough to finish or form tool the dials are the same for each part. The physical size does not matter, as long as you index correctly and machine down to common size. A Pie tape or band that is marked for your diameter can speed the work to get things the same quickly. I have made several offset bands for making wheels that eliminate the practical error of a large mike on a taper. It should be remembered that identical size and taper of the wheels are important to prevent skewed running.

On larger wheels it is sometimes advisable to drill a drive hole that engages the chuck jaw when mounted. a pin from a 1/4 inch bolt will prevent the large wheel from spinning when you try to hog of some material. a spin will destroy your setup accuracy and your tool. ask me how I know. So getting resonable stock removal is within reach without a lot of failure. When set up I have cut 4 inch drive wheels in under ten minutes. So with a pop or coffee in hand, I can do a set of 4 in way under and hour. When I build trucks I usually do the wheels first, and have a stack ready to go.
Big Dave, former Millwright, Electrician, Environmental conditioning, and back yard Fixxit guy. Now retired, persuing boats, trains, and broken relics.
We have enough youth, how about a fountain of Smart. My computer beat me at chess, but not kickboxing
It is not getting caught in the rain, its learning to dance in it. People saying good morning, should have to prove it.

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steamin10
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Re: 12" working railroad

Post by steamin10 » Sat Oct 20, 2018 8:20 pm

PS: I am a hack with a hammer and by no means a professional machiniist. I am trying to tell what I do for the mediochre work that I do. It does not invovle fine fits for the most part but time spent is improtant, as well as a working result. The small engines I have built all run, and all have the same limits as the real ones of fit and clearances.

Nuff said.
Big Dave, former Millwright, Electrician, Environmental conditioning, and back yard Fixxit guy. Now retired, persuing boats, trains, and broken relics.
We have enough youth, how about a fountain of Smart. My computer beat me at chess, but not kickboxing
It is not getting caught in the rain, its learning to dance in it. People saying good morning, should have to prove it.

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BigDumbDinosaur
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Re: 12" working railroad

Post by BigDumbDinosaur » Sun Oct 21, 2018 1:35 pm

rkcarguy wrote:
Thu Oct 18, 2018 10:25 am
Hey, so on a different subject, the Honda GX390 is mounted to it's old pressure washer frame still. There is rubber motor mounts that allow the engine to move/shake a little, should I use these or solid mount the motor? I have to make the plate for the rear of the locomotive frame soon where the engine will mount, and it looks like the pattern will be different if I use the rubber mounts vs. solid.
I suggest the prime mover be solidly mounted to take advantage of the locomotive's mass to dampen vibration.

I'll also reiterate the traction motors should be plumbed in series to avoid the open differential effect. That's how I have them in my F-unit.

BTW, that "torque converter" is actually a hydrodynamic coupling. It doesn't multiply torque.
————————————————————————————————
Science makes it known. Engineering makes it work.

rkcarguy
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Re: 12" working railroad

Post by rkcarguy » Sun Oct 21, 2018 2:16 pm

From what I've seen online, I do want to put the motors in series. I found several posts regarding the collector part of hay bailers that were setup to have the motors run at different speeds. When plumbed in parallel, the faster(less torque) one would jam easily and stop turning and the other would spin faster. In series, only if the jam ran the pressure up to the relief setting, would the hay stop moving.
BDD, I may try it both ways, with the rubber mounts and solid mounted, if both patterns will nest into the plate without interfering with each other. I've always solid mounted, but always had to do to chain drives that went to frame mounted axles. In my automotive experience, firmer engine mounts always made for more shake and vibrations into the car, yet performed better and kept shifting more precise because the engine/trans wasn't moving around. So, years ago the race car got very firm mounts because I didn't care if shook vibrated and rattled, and my daily drivers that I played with I left them stock, or some I modified by filling the voids in the factory mounts with polyurethane to make them a bit firmer. When I tried firm mounts on a daily driven car, it made the dash buzz and rattle, the change jumped around in the center console, etc.

rkcarguy
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Re: 12" working railroad

Post by rkcarguy » Mon Oct 22, 2018 9:22 pm

Steamin, do you generally sharpen a tool with a radius on it to cut the flange radius and flange taper in one shot?

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steamin10
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Re: 12" working railroad

Post by steamin10 » Tue Oct 23, 2018 2:38 pm

On a quick change post I use a high speed tool bit sharpened with about an 1/8 radius to cut the tire. Once skinned the tire and flange are taken in one pass with a formtool to come down to the tire dimension. The taper is set on the compound and requires me to swing things around since my machine is smll and wont take the full cut for tire and flange, leaving me to scratch at the work. With a bigger machine than my 9 inch SB I could hog the diameter and cut the time down a lot with a form tool. I get too much chatter and slip on the drive.

I stone the bit often and keep it sharp, but the tip lasts longer with a small radius, one that matches the root of the flange. My tools cut like butter, but skins destroy them so you must get below the oxide or skin on castings or burnouts on the first pass.

To me, wheels are not a high accuracy job. Not like fitting a cylinder piston and rod assembly. So the tolerance is somewhat open except for the axle that is fitted for a heat shrink. I use one inch or 7/8 stock and the wheel is bored to 1/2 inch. I am currently using loose flange bearings that are uncaged for the truck sideframes, as they are cheap and give a little. Theses are the same bearings that are in wheels that are on most hand trucks. Precision bearings would require a lot more movement of the side frame to stay equalized with the axle tilting out of line. Thats the theory anyway.

I cast my own trucks and bolsters.
Big Dave, former Millwright, Electrician, Environmental conditioning, and back yard Fixxit guy. Now retired, persuing boats, trains, and broken relics.
We have enough youth, how about a fountain of Smart. My computer beat me at chess, but not kickboxing
It is not getting caught in the rain, its learning to dance in it. People saying good morning, should have to prove it.

rkcarguy
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Re: 12" working railroad

Post by rkcarguy » Tue Oct 23, 2018 5:24 pm

Thanks for the info Steamin. Our lathe is huge, I think it's an 16" x 18' long or something like that. But I'm cutting flanges 1/4" deep so I still expect that to be 2 roughing passes and a finish pass. They have a 1/4" round carbide insert type tool that may be a good option for all my turning needs.
I'm thinking it might make the most sense to drill two "drive bolt" holes and drill/ream the center hole on the mill. Then mount those to a hub/stub I can clamp in the lathe and turn the outside profiles.

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steamin10
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Re: 12" working railroad

Post by steamin10 » Tue Oct 23, 2018 5:47 pm

Why use a mill when you have the perfect lathe to punch a hole?

I would approach it from facing the slab and boring the axle hole to get the face profile. Once the ceenter hole and profile are done you can mount the piece on a mandrel made for the bore and finish the opposite side and flange. If you grind a form tool for the flange all the better. A drill press to put a drive pin in the rear side is a good insurance against spin on the mandrel and wont effect the use at all.

You will see what I mean when you set up the first time and turn the chips out. Engage brain before the clutch and think things out. What I do works for me. With a bigger machine, I think the process would change a little. I am a hack with a hammer, and better mechanic than machinist. So my OOPS pile is larger accordingly. But if I can make wheels that roll, I think anybody can.
Big Dave, former Millwright, Electrician, Environmental conditioning, and back yard Fixxit guy. Now retired, persuing boats, trains, and broken relics.
We have enough youth, how about a fountain of Smart. My computer beat me at chess, but not kickboxing
It is not getting caught in the rain, its learning to dance in it. People saying good morning, should have to prove it.

rkcarguy
Posts: 871
Joined: Tue Aug 22, 2017 10:33 am

Re: 12" working railroad

Post by rkcarguy » Tue Oct 23, 2018 6:36 pm

The 8 burnouts I have done so far, were done on the plasma table and have a fair amount of camber to them. I'm concerned that they could kick loose while working on the first operation. Future blanks can be laser cut and will be able to go right in the lathe.

rkcarguy
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Re: 12" working railroad

Post by rkcarguy » Mon Nov 05, 2018 9:52 pm

I shaped and welded up the point rails for the turnout after work today, I'm planning to grind some of the welds smooth and then get them in the mill to cut the long tapers on Wednesday.
Also a question, should I use bronze/brass bolts for the pivot points of the point rails? I'm thinking they would wear, instead of the steel and could be easily replaced.

rkcarguy
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Re: 12" working railroad

Post by rkcarguy » Fri Nov 09, 2018 4:35 pm

I found some bushings that were pretty affordable, ~$1.50 each, 3/8 x 1/2 with a collar on one side. So I'll press these into the point rails at the pivots and where the tie bar attaches and use bolts through them. I figure anything I can do to reduce maintenance and prevent the points from rusting into one piece with the pivots is time and money well spent. I also drew up a tie bar to be laser cut, with a narrowed portion in the center and 4 holes in it. Basically what I'm going to do to isolate the point rails from each other is match drill and bolt in a piece of 1/4" phenolic across the 4 holes, and then zip out the narrow portion in the center (2" wide) with the port-a-band.

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