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.

Moderators: Glenn Brooks, Harold_V

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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 May 24, 2019 12:48 am

I looked at the actual specs on this lathe today. It's a Victor 2418, guessing that's 24" and a 18' bed?
The motor is a 15HP 3-phase.
It doesn't do small stuff very well, I had to thread some bolts I was turning into a coupler nut because the chuck was too big to clamp down on them by themselves.

rkcarguy
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Re: 12" working railroad

Post by rkcarguy » Tue Jun 04, 2019 6:35 pm

Tomorrow I'll be center drilling the axles and pressing the wheels on them for the riding car. The axle material is spec'd at 1.000" +.000 / -.002, so I'm hoping I'll have a good fit with the .998" reamer I used in the wheel bores for a light press. Once on there and gaged properly, they will go to the TIG welder for a few small fusion welds and then back in the lathe between centers for final turning of the tapers.

The lathe chuck unfortunately doesn't run as true holding the 1" axle stock as it did the larger diameter wheels. I measured .0025" of runout which is no-bueno, so I'm going to have to bore a sleeve or something to slip the axles into so the center drill is actually centered.

rkcarguy
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Re: 12" working railroad

Post by rkcarguy » Thu Jun 06, 2019 10:59 am

I pressed together the wheel sets last night and unfortunately have some side-to-side wobbles even though the press fit was really nice. I was able to lock down the tailstock of the lathe and use it to start the axles into the wheels about 2/3rds of the way through and then used the press to finish the job to the right gage. I'm going to have to tack them and tap them around and get them to run true enough so I can finish turn them. Moving forward I'm going to have to have shoulders to press the wheels up against even if I have to weld them onto my axle materials and turn the faces. Not sure if the axle material is egg shaped a thou or so, or what is going on.

Harold_V
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Re: 12" working railroad

Post by Harold_V » Thu Jun 06, 2019 2:53 pm

It is my opinion that you aren't likely to achieve a desired fit if you rely on stock size. It's generally not round, not straight, and certainly varies too much to be trusted for a reliable press fit.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

rkcarguy
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Location: Wa State

Re: 12" working railroad

Post by rkcarguy » Thu Jun 06, 2019 3:55 pm

That's why I'm starting on the riding car wheelsets first as they aren't super important like the locomotive wheelsets. I didn't use heat, I should probably heat up the wheels and then shrink them on and provide a shoulder for them to stop against. I'm committed to the 1" size because I've already got my bearings and hubs and everything for the locomotive and riding car. Using something else larger for axles and turning the ends between centers for my bulkhead flats is an option.
At lunch I went and tacked up the "narrow side" of one of the wheelsets and then tapped things around with a mallet and got the wheels to run true side to side within about .010". Again they are rolling very concentric , but I'm fighting back and forth wobble because for whatever reason the axles aren't pressing into the bores perfectly straight. I just need to get them close and then when I cut all my tapers everything will be all good.

rkcarguy
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Re: 12" working railroad

Post by rkcarguy » Thu Jun 06, 2019 4:29 pm

Axle material is stressproof steel. It has that corkscrew finish on it, I thought it would be pretty good stuff.

Harold_V
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Re: 12" working railroad

Post by Harold_V » Thu Jun 06, 2019 6:29 pm

That in and of itself presents another problem, as the carbon content of Stressproof is high enough to heat treat. You're going to create issues from the HAZ, so keep that in mind.

Stressproof is a great choice, but not the best one to make if welding gets involved. (Welding is not recommended)

H
Wise people talk because they have something to say. Fools talk because they have to say something.

rkcarguy
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Re: 12" working railroad

Post by rkcarguy » Fri Jun 07, 2019 10:17 am

What I'm doing is just little quick fusion welds with the TIG to keep things from moving, doesn't build hardly any heat. It's a trick I've used for years, you can't loiter though. Punch it, wet out about three little puddles and then kill it, but let your after flow gas continue to flow onto the weld until it stops. I have had cracking of these little welds in the past on stressproof, and have found a little bit of brazing rod or S1B works nicely in this case, just weld a small bead as quick as possible to minimize heat. So far this stuff has fused to my wheels just fine.

rkcarguy
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Re: 12" working railroad

Post by rkcarguy » Fri Jun 07, 2019 11:45 am

Harold, could I use hot roll mild steel and turn the ends between centers for the axles for my future flat cars? We have some 1-1/2" round hot roll remnants left over from some heavy custom railing we built for a parking garage entry/exit ramp. I'd simply turn each end down to 1", heat the wheels and drop them onto the ends and they should square up nicely against the shoulder.

Harold_V
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Re: 12" working railroad

Post by Harold_V » Sat Jun 08, 2019 1:15 am

Sure. A reasonable choice, although not the greatest material to machine. The best part is welding won't create any issues for you, and that should be a consideration. Modern day hot rolled may be better controlled in regards to size and roundness, but back in the day, it was always oversized, and certainly not round. Not a problem for a guy with a lathe, though, especially if you work between centers.

The thing about not welding certain materials. 303 S is not recommended for welding, but it can be welded. In regards to Stressproof, I imagine that if you approach it much the same as you would 4140, you'd have reasonable results.

The little tacks you described are likely acceptable (you're not sending anything in to space), but there is the small risk of fractures, although in the scheme of things they shouldn't present anything more than an inconvenience. Certainly not life threatening. :-)

I've followed your build with considerable interest, and am envious of your welding capabilities (and overall ingenuity). Wish mine looked that good.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

rkcarguy
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Re: 12" working railroad

Post by rkcarguy » Sat Jun 08, 2019 3:32 am

I appreciate the kudo's Harold.
I am self taught in welding, started my career as a machinist and my interest in cars led me to needing to learn to weld. I electrocuted myself many times and snubbed the tungsten into the weld I don't know how many times haha.
I think the best advice I can give with TIG welding, is that for awhile I was too cautious. I would set the machine amps so I could floor it, and would ease into the pedal and slowly build heat until a puddle started to form and then start welding. This would overheat the part and by the end the weld would look like crap. Now I run the amps quite hot, dive in with a lot of pedal from the get go and then move quick, stuffing rod and increasing speed or reducing power if needed as I move along. I don't have the best hands (shaky) so I often use something to rest or slide my hand along so my welds look better.
It takes practice, I've been TIG welding on and off for 20+ years now and I still usually warm up on some scraps before I go weld up my parts.

The mild steel round in the rem rack is pretty rough. What I did was purchase 3/4" 4 bolt flanged bearings for my bulkhead flats. They are still rated at over 1300#'s each and will be plenty strong and look a lot better with their smaller size on the truck frames than the 1" versions. This will also allow me to turn one end of the axle to 1" and center drill it, flip it around(it will be a several thousandths out of concentric at this point) and then turn the other end and press/tack on roughed out wheels. Then, the assembly goes between centers where both ends of the axles are turned to 3/4" and the wheels are finish cut to size so the wheels run concentric with the ends of the axles even though the rest may be out a bit. I can run a bolt through my drive dog hole in each wheel that will pick up the jaws on the chuck.

I find mild steel and the A572-Gr50 plate to machine really nice with carbide as long as it's "loaded" and your lathe has the power to do so. For instance I took .100", .100", and .050" depths of cut when roughing my wheel surfaces and they came out really nice....not that it matters because I'll have to turn the tapers anyway after I get them trued up.

As far as the tacks are concerned, it's more extra insurance things aren't going to move being I have no shoulder to press up against or if I have a derailment down the line. Over the years I've done that on many things where a press fit simply wasn't enough to hold one part to another and things would slip. The small fusion welds are easily turned out on the lathe if the parts need to be disassembled again.
If cracking becomes an issue (for some reason I've had issues before with cold rolled steel and steel TIG rod), stainless rod or silicon bronze rod can be used. The SiB is great stuff because it has a lower melting point than the steel so you can lay down a weld without actually deforming the steel and it's still plenty strong. I used it around my coupler boxes on the locomotives pilots so I could doctor up the weld with a Dremel without having to grind my way through a really hard steel weld bead.

rkcarguy
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Re: 12" working railroad

Post by rkcarguy » Tue Jun 11, 2019 10:32 am

I'm slowly getting the wheels trued up within reason on the axles, and got all the brake shoe parts ran through the laser yesterday.
I also drew up some simple parts for a wheelset truing stand that I had laser cut, basically a pair of stands that take two ball bearings each with a dip between them for the axle to sit in. This way I can set the wheelsets into the stand and tap them around instead of putting it back in the lathe between centers every time to measure runout.

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