Author Topic: Commentary (need feedback from steam guys) - 2-8-0 Imported for HALLMARK MODELS  (Read 2532 times)

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peteski

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Yes Max, you are amazing!
My eyeballs were spinning trying to keep up with the video (it is way too fast).  It must have been an optical illusion that the drivers were actually were getting closer together in some instances.  But it was probably the wobble.  I agree that removing all the rods form the main driver, then running the model (much slower) should give us a good idea how the main drivers behave.
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mmagliaro

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Ha!  Let's see if I guessed right before calling me "amazing".   LOL!

There's a little more to the story.  After you shim the play out of that axle's bearings, you MAY find that the engine
will jam, or at least bind, at one spot in every rotation.  If the drivers are a little out of quarter, the only thing
letting them get around could be the slop in that driver.  So if it's not sloppy anymore, it might bind.

That's why you might have to shim the bearings on the back and then try it just on the front, to see which way runs best.
Remember, by doing that, you are holding the driver more forward or rearward.  One way or the other might "fix" the quartering and one way might make it worse.

But we'll get to that if it's true.  First, pull the rods and run the engine on its back and then on the track and see if it works better.
It might be dodgy getting it to run without rods.  Just a single driver might be too slippery to actually move the engine, but we'll see.

seusscaboose

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Max
Thank you for your feedback and advice

We will give this a try

Stand by for a few days my friend(s)

:)

Eric
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garethashenden

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Max,

I agree that it looks like a quartering issue and someone (maybe the factory) added extra slop to get it to run. Won't he need to fix the quartering anyway? If the slop is taken out and the quartering not fixed then the whole thing can bind up. I have no idea how the wheels are mounted on the axles, but one of them needs to be turned slightly to correct the quartering issue.

peteski

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Also, a video from the side looking at the drivers straight on (and spinning as slow as possible) would be helpful.
--- Peteski de Snarkski

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mmagliaro

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Max,

I agree that it looks like a quartering issue and someone (maybe the factory) added extra slop to get it to run. Won't he need to fix the quartering anyway? If the slop is taken out and the quartering not fixed then the whole thing can bind up. I have no idea how the wheels are mounted on the axles, but one of them needs to be turned slightly to correct the quartering issue.

Gareth, note in my comments about 2 posts back that I said that after he shims the driver bearings to remove the slop, it might bind and then we'll know for sure if there is a quartering problem.

He may not have to turn a driver on an axle.  Bearing in mind that these are cast brass frames, there is sometimes error in where the bearing slots are because they are cleaned up and trimmed by hand after casting.  They don't all come out the same the way a commercial non-brass frame does.  So it could also be that the bind occurs because that axle slot is a little too close or far from the next driver.  If that's the problem, shimming it one way or the other may take out the wobble and fix the bind at the same time.

I really hope he does not have to turn one of those drivers on an axle.  Brass engine drivers are notoriously tight.  I have had more than one that were so tight I could not get the axle out with a wheel press or even by placing the driver in a V plate and using a punch to knock the axle out of the center.

It's also possible that there is a quartering problem in a driver other than the one we're looking at, and the wobble is just showing up on the geared driver because that one has the most play in the bearings.  The quartering error will shove whatever driver is willing to move the easiest.   That will be a matter of leaving the rods on, and leaving them pinned to the geared driver, but then only pinning them to one other driver at a time to see if certain driver pairs run well together.

This is a nasty problem because the error is slight - after all, the engine does still manage to run.  So it might not be easy to see.

seusscaboose

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Max/John (& others)
My friend Jerry should be logging on and joining the conversation shortly...  he has the engine.
EP
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woodone

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Hi Guys.
Well here is the latest, After a brief apology to the poor video.  1st time doing that.
Hard to video now has I have the Drivers off the axle.
Here is what I see. The bearings are very well fit, very little slop in them fitting into the frame. Has a mater of fact it takes a bit of fiddleing with them to get them to slide into the frame. The bearing fit the axle well too. I measured the Axle where there was not any wear and read a diameter of 0.1165-2.95MM. Where the bearings were on the shaft I measured 0.0115.
I was able to get the drivers off but not with out a fight. I had to make up some tooling so I could support the drivers right at the hob so i did not put any pressure on the driver except right at the axle. Piece of steel with a 0.115 slot so I could slide the axle into the steel plate. I also made a small brass washer .030 thick to place between the hb of the driver and the steel plate to keep me from applying any pressure on the outer rim of the drivers. I then used a NWSL press and removed the drivers. I think that they wre loctighted on, has the pressure to get them to move almost exceeded the max the press could muster.
Now when I try to press back on the shaft takes the paath of least resistance and goes on cockeyed!
Thinking of boring out the drivers-and then use silver epoxy them into place. Will make some more tooling to hold the axle and drivers at a 90 degree angle to the shaft and hold in gauge at the same time. When I say bore out the drivers I am only looking to take .001 out.
There are serations on the axle where the drivers fit. It measures 0.118 at the upset serations.
Replacements? Axle diameter 0.116-2.95 MM ( I am thinking it is really 3.00 MM) Brass driven worm wheel is .542 OD 28 teeth and 0.118 wide.
Drivers are .775-7.77 on the OD .725-.730 at the diameter were the tire would hit the rail head. 
Thanks for any input.
Jerry AKA woodone   

mmagliaro

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A machined block, the correct width, with a slot in the middle to clear the axle gear, will do the trick for holding the drivers at a perfect 90 degree angle to the axle while the epoxy hardens.

So... before pressing the drivers off, did you check them with a caliper or some other means to see if the distance between the driver backs really varies around the circle of the drivers?   Were they really on the axle crooked?

Before pressing them back on, I'd make sure the drivers themselves aren't bent by laying them on their backs on a flat surface and making sure there's no "bow" in them.

I don't think there's anything more I can do from here without having the engine in my hands.    Holding them square with a block while the epoxy sets sounds like a good idea.

One other thing, although it's probably too late for this now that the wheels are pressed off.  I know you said the bearing fit was snug, making it hard to get them down in the slot.  But did you get them in, put the cover plate on, and then actually try to see-saw that axle/driver set up and down and side to side in the slot?  Sometimes they are snug at one point in the slot, making it tricky to get them in, but once they are all the way down in the slot, there is more room and they wobble.


woodone

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Thanks Max for the input.
Bearings,  your last question first. The bearings are made of round brass-bronze. The have a grove slot machined into them that slides into the frame and sits in a rounded seat. The bearings have a flat place machined into them that faces the cover plate which keeps them from turning when the axle is being driven. You can't see the axle that well while in the frame and turning. I could watch from the top side and did not see much movement.
The drivers were not in gauge.  I measured with an NMRA gauge. Run out was not measured has I could not get a dial indicator set up to follow the tread. But was able to check side to side with a dial indicator. Not very accurate but 0.060 is what I was able to see. Small parts are hard to hold steady for the dial indicator not to push the model sideways.
I see that Greenway Products has drivers. but at about $18.00 each? I would have to change all the drivers so they would match. Let see that's  8X18   OUCH!  that's $144.00 .
Wheel size?? An I correct in thinking that 72" drivers would be close? Tread diameter best I could measure is about .725.
Thanks again
Jerry

mmagliaro

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You can just measure the back-to-back wheel spacing on that axle with a caliper.  It doesn't have to be so perfect as what you can measure with a dial indicator.  Just measure at 6 places around the wheel and see if they are all the same (within .005" or so).  For the kind of wobble we are seeing, which is pretty extreme, if those drivers are not true on the axle,
you'd be seeing variations of .030" or even .060" or more.  If you don't, then the drivers are probably fine on the axle.
(and this is probably all a moot point now, since you have pressed them off).

The tread diameter is .725.  .725 * 87 = 63.075, so those are 63" drivers.

Note the Greenway price is for a whole axle with two drivers on it.  So you would need 4 sets if you want to change them all out to match = about $80.  Not exactly cheap, but not as much as you thought.  The idea of the Greenway axles is that you would eliminate any mounting problem.  The axle/driver sets all come ready-made, pressed onto the axles and quartered correctly.  you would just have to adapt the bearing slots in the frame to accept whatever bearings are on the Greenway drivers.  If you are lucky, the frame slots would be a little small and you could adapt them with a little filing.    You would really have to call Greenway and talk details with them to see what those bearings look like.  They might not have the little slits in the side.  They might be the type with "ears" on the outside that just drop in the slots and stay put from the ears.

My point about the bearings was just to grasp the drivers between your thumb and index finger, and try to wiggle them up and down, and fore/aft, diagonally, with your hand, while the whole thing was mounted in the frame with the cover plate on.  You can't go by what you can see with it running.  It's more what you can feel and see when you just try to move the wheels around manually.

I understand the kind of bearings you mean.  They might easily be able to ride up and down in that slot quite a bit.  You might need a shim on the top of the bearing ("top" when the engine is flipped on its back, so the shim would go between the bearing and the cover plate).


peteski

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I'm not sure if I'm understanding Jerry's write-up correctly, but it seems to me that he jumped into removing the drivers off the axle without much measuring or testing as to that the problem could really be.  I would have tried really hard to verify what the problem was before disassembling the entire driver set.
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mmagliaro

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I'm not sure if I'm understanding Jerry's write-up correctly, but it seems to me that he jumped into removing the drivers off the axle without much measuring or testing as to that the problem could really be.  I would have tried really hard to verify what the problem was before disassembling the entire driver set.

I am afraid that is my sense of it.   Jerry,  I hope that you did not create a much harder problem by assuming the drivers were not square on the axle before really measuring to see if they actually were. 

woodone

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When I see with a dial indicator that there is .060 side movement and there is only oneplace that a wheel gauge will fit there is some thing WRONG! I removed the drive axle with wheels and rolled them across a flat surface,
The drivers should maintain at 90 degrees to the flat surface- not so, you could see with your eye there was a real bad problem.
Believe me I looked at all ways to correct before the press came out.
Sat on the work table for several days at a time before trying some thing else only to come back to the same conclusion.


peteski

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When I see with a dial indicator that there is .060 side movement and there is only oneplace that a wheel gauge will fit there is some thing WRONG! I removed the drive axle with wheels and rolled them across a flat surface,
The drivers should maintain at 90 degrees to the flat surface- not so, you could see with your eye there was a real bad problem.
Believe me I looked at all ways to correct before the press came out.
Sat on the work table for several days at a time before trying some thing else only to come back to the same conclusion.

Well then, that clears things up for me.
--- Peteski de Snarkski

-"Look at me, I'm satirical!!!"
-"Look at me, I'm anal retentive!!!"
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-"Look at me, I'm snarky!!!!"
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-"Look at me, I'm not negative, just blunt and honest!!!"