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Author Topic: After 7 years of faithful service, the gear failed...  (Read 10347 times)
Barry BBT

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« Reply #15 on: July 07, 2010, 12:56:59 AM »

Kevin,

I think the lower weight of the 4-4-0 and 2-6-0 has a great deal to do with they're lasting better.

The axle diameters have to be the same since I have interchanged them from one to the other.

Maybe some of the problem is we perceive the 2-6-0 and 4-4-0 as being smaller locos (true) and the Connie just seems more robust, stronger and in it's image should be able to pull more so we try.

Barry - BBT

P.S. Just to salivate......I am updating the K-27.
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Kevin Strong


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« Reply #16 on: July 07, 2010, 06:54:30 PM »

I received the gear from NWSL yesterday. It is indeed Delrin (or some other kind of plastic), not brass. No biggie on my part, so long as it fits snugly on the axle and does what it's supposed to do.

I took the 4-4-0 gearbox apart last night to examine the gear. Firstoff, that's not quite the easy task I was hoping it to be. You've got to remove all four drivers off their axles (which was okay since a few of them had worked a touch loose anyway), then tap out the retainer pin that holds the motor end cap in place. Once you do that, you lift out the motor and gearbox, being careful to not lose any of the suspension parts (springs, journal boxes) to the nearest parallel universe. Hint - when pulling off the eccentrics for the valve gear, grab a clamp to keep everything held together once it's off the axle. You'll need two clamps, one for each set of eccentrics.

Once I opened up the gear box, I found the gear had not split entirely, but had minute fractures around the hub that allowed the gear to slide to where it was not engaging the knurling on the axle all that well anymore. The gear itself was still fully intact. I thoroughly cleaned both the gear and the axle, mixed up a small bit of JB-Weld, smeared it around the axle, and slid the gear back in place. I don't know how long that's going to last, but we'll see. Since the gear itself is not split, it may go back to slipping on the axle, at which point I may replace the gear or just have at the axle to increase the grip of the knurling a bit.

I haven't gotten to the 2-8-0 yet. I will take photos of that process for an upcoming GR Basics column on locomotive repair.

Later,

K
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Loco Bill

Model Railroading since 1947


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« Reply #17 on: July 07, 2010, 11:34:49 PM »

Kevin,

Great Idea for the Article!!   Please let us know what issue it will be in!!

Thanks
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Loco Bill,
Roundhouse Foreman
Missouri Western Railway

Unnofficial Historian of Bachmann Large Scale Products
Kevin Strong


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« Reply #18 on: July 08, 2010, 02:53:28 AM »

The 2-8-0 gear replacement went very smoothly. I did manage to send one of the bearing block springs into a parallel universe, but I found a suitable replacement. The NWSL gear is a bit tight going on, so you'll have to tap the axle with a hammer to get it on. Do yourself a favor and use a piece of wood on the end of the axle and hit that, lest you slightly deform the end of the axle and can't get it through the bearing in the bearing block. It's nothing a quick once-over with a file didn't fix, but better to be safe.

I'm also happy to report that the JB-Weld fix on the 4-4-0 gear seems to have done the trick also. Both locos are moving under their own power, with no sign of slippage. Ask me again in a year or two how things are holding up, but for now they look promising.

Oh... look for the article in the December or February issue.

Later,

K
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Doneldon

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« Reply #19 on: July 09, 2010, 03:01:22 AM »

Kevin-

I've used JB materials on a number of fix-it jobs (not trains) and found it to be a good product.  It should work very well on your loco because there isn't really much pressure against your repair.  I wonder if it couldn't be used for slipping or even broken gears which want to rotate around their axis.  I think it would be worth a try if anybody has such a problem.  BUT, I must point out that this stuff needs a really clean surface to bond properly.  Clean it up and then wipe it with naptha or alcohol.
                                                                                                -- D
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guy tyteca

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« Reply #20 on: July 09, 2010, 10:32:10 AM »

TRR #3, the railroad's venerable Bachmann outside-frame 2-8-0, broke its main gear while pulling a short freight into Shade Gap. EBT #3 was dispatched to pull the train to Blacklog, then pulled #3 to the EBT's Rockhill Furnace shops for repair.

The TRR management considered the options available:
1) Buy the replacement plastic gear from Bachmann ($3 plus shipping)
2) Buy the replacement wheel, axle and gear from Bachmann ($20 plus shipping)
3) Buy a replacement brass gear from NWSL ($12.95 plus shipping)
4) Buy a BBT motor/drive (Price unknown; well worth it, but not in the budget)

The plastic gear was kicked around, as this one lasted 7 years, and one could buy a handful of replacements for the cost of the NWSL gear. The replacement wheel/axle assembly was deemed unnecessary, as switching out a gear is a fairly mundane task for the shop crews. In the end, they opted for the brass gear from NWSL. The plastic replacement gears may last another 7 years, maybe longer, but maybe shorter, too. The brass gear isn't going to break. Due consideration was placed relative to wear and tear on the other gears in the drive, but failures of those gears have thus far proven rare.

NWSL part # 2226-6

Once the TRR receives the replacement, crews will give #3 a proper overhaul, making sure she's good and ready to return to the road in full form.

Later,

K

I just saw this post a couple of days ago. I do have the same problem with a brand new 2-8-0 Consolidation. I want to draw your attention on the following : the first option quoted = Bachmann plastic gears ($ 3.00) is wrong, since the gears they advertised are those inside the gearbox, not the main gear on the axle !
Since mine is new and less than one year old, I will ask for a free replacement !

Bet Regards from hot (well today) Belgium.

Guy Tyteca
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Kevin Strong


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« Reply #21 on: July 09, 2010, 10:38:33 AM »

My only concern with using the JB-Weld to fix a broken gear (split in one or more places) would be making sure when the gear is put back together that the spacing on the teeth at the break are still even. (That goes for any kind of glue, really.) If you can do that, and the glue holds, then you're good to go. But depending on the difference between the axle diameter and the bore on gear, that may be easier said than done. You may have to do some work to the bore of the gear to ensure a tight fit at the broken joint, then rely solely on the JB-Weld to hold the gear to the axle. Obviously, if a replacement gear is available, that's the preferred method, but 'tis not always the case.

Later,

K
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Kevin Strong


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« Reply #22 on: July 09, 2010, 10:44:51 AM »

Quote
...the first option quoted = Bachmann plastic gears ($ 3.00) is wrong, since the gears they advertised are those inside the gearbox, not the main gear on the axle !

Ah, so it is! Good catch. I suppose I would have figured that out once I received it, only to have to wallow in my own stupidity for not looking closely at the photo. Embarrassed Glad I went with the NWSL option. Thanks for pointing that out...

Later,

K
« Last Edit: July 09, 2010, 10:47:12 AM by Kevin Strong » Logged

Loco Bill

Model Railroading since 1947


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« Reply #23 on: July 09, 2010, 01:39:00 PM »

Agree with Donaldson on JB weld.  I also like to rough up the surfaces as well whenever possible.  Especially if a metal part is really slick, or if a plastic part is really shiny!!  it doesn't take much, just a hit with 200 grit paper.    Also recommend the regular JB instead of the 5 minute type, on items like gear trains, as opposed to something fixed like a structure joint where the 5 minure type is fine.    I think it would work well on a slipping gear, provided it didn't get out of round in some way.
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Loco Bill,
Roundhouse Foreman
Missouri Western Railway

Unnofficial Historian of Bachmann Large Scale Products
Barry BBT

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« Reply #24 on: July 09, 2010, 02:09:59 PM »

Kevin, et al,

For the record;  I have repaired (?) a few of the axle gears from a 2-6-0 Spectrum and the 2-8-0 Connie.

After removing the gear from the axle, usually with several cracks around the gear hub.  Clean everything up, old grease, etc.  Trial fit brass tubing for a fit on the gear hub.  Slice a couple of rings of the brass tubing about 1/8" thick.  Mix up a small batch of JB Weld (not the quick stuff).  Apply the JB Weld around the hub of the gear, press in the brass tubing slice,
Turn the gear over and repeat on the second side.  Clean up the JB Weld excess.  Let it cure for 24 hrs.  Re-install, Run.

Barry - BBT

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Doneldon

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« Reply #25 on: July 11, 2010, 02:52:14 AM »

The JB Weld isn't exactly used as a glue in this application.  It's more of a support to either hold the slipping gear in place, be used on both sides of the gear and through holes in the gear to hold the gear itself together (but not as an adhesive), or both.
                                                                                                                -- D
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Barry BBT

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« Reply #26 on: July 12, 2010, 12:14:23 AM »

D -

No argument.  I liken what I have been doing is like concrete and rebar.  The JB Weld holds everything in place (concrete) and the brass is for strength (rebar).  What I do know.... it is working.  It is not my best suggestion, but not everyone has the budget for it.

Barry - BBT
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