SP NG Diesel #1 (GE 50T) - Triennial or Bust

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senorgilamonster
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Re: SP NG Diesel #1 (GE 50T) - Triennial or Bust

Post by senorgilamonster »

I didn't know that you could use Forstner Bits on aluminum. At any rate I found a 1 x/32" HSS drill bit on Amazon that looks like it is just the thing. Apparently I didn't do my web search right the first time.

I suspect that the bar is touching. There is quite a bit of bar that extends beyond the cutting tip...and I did not make the original drill hole particularly deep. I may have to allow for that and drill to a greater depth before boring.

As always - thanks for the tips.

On another note - the inside of the holes that I drilled on the sides of the pillow blocks (the edge that slides up and down on the bronze) was a bit rough especially compared to what you could mill. I took a piece of 1/2" dia steel rod (same OD at the bronze), and wrapped a piece of 120 grit wet/dry sandpaper to it. Attached it with plain old double sided tape. Made certain that the overlapping end would spin the correct direction and chucked it into the drill press. Less than a min on each edge polished 'em right up. The bearing practically jets down the groove if you tilt it off level. I'll probably go back and hit the grooves with a finer grit for the final finish.

I might run our of work on the trucks before the new tooling arrives.
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rkcarguy
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Re: SP NG Diesel #1 (GE 50T) - Triennial or Bust

Post by rkcarguy »

I use all kinds of stuff I'm not supposed to on aluminum:) It puts out a pretty wide chip, so you'll need some good power!
Looks good, ad yes it should clean up nice with a finer grit paper.
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NP317
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Re: SP NG Diesel #1 (GE 50T) - Triennial or Bust

Post by NP317 »

Having too polished a surface might not be the best for Aluminum.
Leaving some surface imperfections to hold lubricant has merit.
~RN
Pontiacguy1
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Re: SP NG Diesel #1 (GE 50T) - Triennial or Bust

Post by Pontiacguy1 »

According to the bearing manufacturers, whichever is the REVOLVING member should be pressed or otherwise rigidly attached to the bearing. So, in our case, the axle is revolving while the axle box remains still. Thus, it is OK for the outside diameter of the bearing to be loose in the axle box (and give it some play if necessary), but the axle and the inner ring of the bearing should be locked or pressed together.

Why do this? Well, if you don't have a press fit with the revolving member, then they are no longer revolving together exactly, they are rolling on each other. In other words, the bearing Inner Ring bore and the shaft will roll against each other while revolving. Dirt/grit WILL get in there and will start wearing down the shaft. This is not good. It is also not the way the bearings were designed to work. Ball bearings do not like shock-loading (bouncing/hitting), so it is better on them if the revolving member is rigidly attached to the bearing. These are the reasons why you have setscrew and locking collar bearings that are very common in industrial and agricultural applications. You can also work-harden and break a shaft when it is doing this, I've seen it happen. The shock-loading thing is also why ball bearings were never used in full-size railroad locomotives/cars. They are, however, extremely good for our size of locomotives and cars.

True story: Have an older Craftsman 12" wood band saw. Had adjusted it several times over the years, but then it finally got to the point where I was having trouble keeping the saw blades on it. They kept wanting to roll off one way or the other, and it was getting to be a very finicky machine. I started checking things and the main shaft that powers the lower wheel where the blade runs had some looseness and wobble in it. I figured I had a bad bearing, so I tore it down. It was NOT a bad bearing at all. The manufacturer had put the shaft through the ball bearings loose. When I pulled the shaft out, it was worn in over 0.030" where each of the bearing's inner rings had been riding. This is because the shaft had been rolling in the inner ring of the bearing instead of being locked to it. Sort of like a tire rolling down a road, it will eventually wear. Get a little bit of dirt in there, and now it is sanding itself down and will wear faster. I made a new shaft, bought new bearings for it, pressed it all together, and it's been that way for 10 years now. Guess what? I've not had to adjust that machine at all since doing that.

Not following these general guidelines doesn't mean that your project won't work or run, but it won't work as long and eventually there may be problems that will crop up from it. It may take a while for the problems to show up. There is a reason why manufacturers suggest their products be used in a proscribed way... They've done the research and know how to make them give the best performance.
rkcarguy
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Re: SP NG Diesel #1 (GE 50T) - Triennial or Bust

Post by rkcarguy »

Good info Pontiacguy.
Another thing I'll toss out there regarding grease and oil in an open environment, is that dirt and dust will stick in it and cause wear. I used to dirt bike race in Eastern Washington with my dad and the loamy sand would stick to the chain lube and just ate sprockets and chain alive. We switched to Maxima's chain wax, it's sprayed on, and dries leaving a slippery yet non-sticky lube, and it got things back to a normal as far as chain and sprocket wear. As a bonus, the chain also isn't sticky and greasy if you are working with it or accidentally get up against it.
The only downside I discovered is when it's cold the chain would be a bit stiff until things started moving.
Pontiacguy1
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Re: SP NG Diesel #1 (GE 50T) - Triennial or Bust

Post by Pontiacguy1 »

I will say this... these recommendations will work fine on cars and on diesel/electric locomotives. If you are using ball bearing in the drive wheel axle box of a steamer, it needs to be a tight fit in the OD as well as pressed on the axle shaft. Why? So that the back-and-forth of the piston thrusts aren't slamming the bearings back and forth. Also, that can mess with your center-to-center distance which affects your rod bearings. Any misalignment ability on your main drive axles on a steamer needs to be made into your axle boxes. In other words, your axle boxes should be able to tilt a little bit to allow for a bump hitting one side but not the other.

Hope this makes sense.
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senorgilamonster
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Re: SP NG Diesel #1 (GE 50T) - Triennial or Bust

Post by senorgilamonster »

Got the 16" bed today and rebuilt the lathe. It is long enough to do the job now. Still a bit squirrely to face the ends, but as I learn to use the steady rest, I think that will get easier. Once faced and put on the live center, no worries.

I have an unusually high number of parts left over (even by my standards).

I managed to drill the hole for the change gear adjusting stud off by about 1/64th...and cannot get the arm over the stud, so today - no drive on the lead screw. I'll have to widen the groove on the arm I think.

There is also a cover that goes over the lead screw that the instructions totally skipped and I didn't think about it until it was all assembled. I have to take off the lead screw to drill and tap the holes (I think). Since the DROs come in a couple of days, I'll leave it like this until they arrive since I have to do some tear down then anyway.
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rkcarguy
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Re: SP NG Diesel #1 (GE 50T) - Triennial or Bust

Post by rkcarguy »

That's cool you were able to extend/replace the bed. I'm not a huge fan of the steady rest, up until now(working in office), I always had access to a lathe big enough that my stock could go through the spindle.
Darby Johnston
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Re: SP NG Diesel #1 (GE 50T) - Triennial or Bust

Post by Darby Johnston »

Hi,

I'm not sure sure if you are still looking for photo references but I just saw this nice side view come up in one of the ebay sellers I follow:

https://www.ebay.com/itm/Southern-Pacif ... SwvP9apBso

(no relation to the seller besides having purchased from them before)
0351
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Re: SP NG Diesel #1 (GE 50T) - Triennial or Bust

Post by 0351 »

Another great reference photo I recently came across.
Also apparently a sister locomotive of SPng #1 sleeps in the big railroad shop in Guatemala City.
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senorgilamonster
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Re: SP NG Diesel #1 (GE 50T) - Triennial or Bust

Post by senorgilamonster »

To key, or not to key? That is my question:

The 7" wheels that I bought pre-machined have nice keyways in them. It stands to reason that I should take advantage of them...

The center bore is .74 for a .75 axle I am assuming that this is for a heat or press fit. Seems like I need to turn my axles down to something like.743 (I have no way to increase the bore diameter reliably anyway).

Should I try to cut a keyway into my axles? If I do, can I still use the heat method to get the wheels onto the axles, and if so, how do I get/keep the keyway aligned before the wheel cools too much to be adjusted?

Keyway would seem like best practice, and I am going to have to figure out how too cut them for the drive sprockets anyway. (no milling machine or broaches - just lots of redneck Youtube videos).
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Harold_V
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Re: SP NG Diesel #1 (GE 50T) - Triennial or Bust

Post by Harold_V »

First, lets determine how you're measuring the bores in those wheels. If you're trusting a caliper (doesn't matter if it's digital, dial or vernier), that's a huge mistake. You should be using a telescoping gauge and micrometer unless you have a dial bore gauge, or an intrimik.

It's important that you understand what constitutes a press or shrink fit. If you shoot for .003" interference, you're not going to have a good day.

I'm not a fan of LocTite (nothing wrong with the product, it's just not my choice for making fits), but in this case it might be the wisest thing you could choose to use. It will eliminate assembly problems, and would allow the use of a key. That's assuming you can come up with a way to cut them. They are not something that should be cobbled---as they're intended to be a proper fit, otherwise they are prone to failure. That said, if you're hell bent on heat shrinking, you can still use a key, just make it longer than the journal, so it keys before the wheel gets started on the axle. Once the wheel is in place, it can be cut flush with the wheel hub face.

If you decide to go the LocTite route, it would be prudent to select the proper product, and adhere to their recommendations for its use. Clearances are critical if you expect proper performance.

H
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