Spectrum 4-4-0 different gear problem

[Fred2179]

I have a 1:20.3 spectrum 4-4-0 and it stopped moving - cracked axle gear, I thought.  (I already replaced one on my 2-6-0.)  So I ordered the axle from Parts and got on with the surgery.
Imagine my surprise when I realized it wasn't the axle - it was the first gear pair and the spur on the worm was completely worn away!



Anyone know where I can get a replacement?  The whole motor/gearbox pair is available, but for $50.40.  The gear looks just like the one on the axle, but different shaft and the extra spur attached to it.  Guess I could pin the axle gear to the smaller spur gear and use some brass tube in the hole. . .

[Greg Elmassian]

It would probably be best to determine what caused the problem in the first place.

And that gear that engages the worm is different from ALL the rest of your gears, notice the angled teeth to match the angle of the worm?

You need the correct replacement. Isn't it on the parts list, or have you already determined that the gearbox is only sold as a unit.


Greg

[Fred2179]

It would probably be best to determine what caused the problem in the first place.
And that gear that engages the worm is different from ALL the rest of your gears, notice the angled teeth to match the angle of the worm?
You need the correct replacement. Isn't it on the parts list, or have you already determined that the gearbox is only sold as a unit.

Greg

I think it's a bit late to figure out why it happened - I bought this engine recently.  My understanding from slot cars is that incorrectly lubricated nylon gears would decimate a brass gear very quickly.  In trains, I often see the reverse.

Yes, I did see the angled teeth, and No, there's no parts except the axle gear.  Bachmann wants $50+ for the replacement motor/gears, and unless someone comes up with a scrap drivetrain I think I'll end up paying it.  These locos are so nice it would be a shame to junk it.

[Greg Elmassian]

If you know Dave Goodson, he might be a source.

Greg

[Fred2179]

After much research and discussion, it was suggested that the gears in the 2-8-0 gearbox are probably the same, and that gear set and the individual gears are listed as parts.  "Sold Out" of course.

https://estore.bachmanntrains.com/index.php?main_page=product_info&cPath=69_142&products_id=9646

[armorsmith]

Fred, if you are willing to take a gamble, contact WM Berg, or Stock Drive Products and see what help they might be able to offer. Not on a combined gear like that one, I have had them recommend replacement gears in the past by sending the worn out gear to them for evaluation. I have always had my original returned.
They may be able to offer two individual brass gears that can be soldered together.

[Fred2179]

I have no problem with gambles, and I may try the NWSL 24 tooth gear.  Or I'll wait for  new stock of the gears - plenty of other projects!

Incidentally, my replacement axle is a bit different. It has a flat on the axle, and thus the gear hole is a "D".  This is what I got from Parts:



The NWSL replacements are not "D" shaped, so this is a recent change.  As Mr K points out, they probably won't spin on the axle if they crack (dubious - I'd expect them to disintegrate if they crack on the squared axle!  We will see. . . )

Anyway, my 4-4-0 axle gear shows no signs of wear and it is the same "D" type, so perhaps it was already changed.

[Stokerman]

North West Short Lines (NWSL) is no longer an option I'm afraid. They've sadly pulled the plug on their business within just the last month or so. I was hoping that they'd sell the business to some enterprising young person because they've long been such a valuable resource, but I've heard nothing along those lines, so assume that it is a done deal and custom model railroad gearing is now at a dead end.

[Greg Elmassian]

Check the NWSL web site, they announced the business has been sold to an employee, and he will continue, moving the business a few towns away.

So after he is settled, him him up for one of these gears. (and keep your motor screws tight so the gear does not come out of mesh again 

Greg

[Fred2179]

I am reliably informed that the NWSL gears (I have ordered one but it is waiting for the reorganization,) do not have the "D" axle shape.  Not clear how you would fit one.

And that raises the question of these replacement axles and gears from the Parts dept.  If they made a different gear style, did they use different plastic for the gear?  Only time will tell.  I note my existing gear and axle is the same "D" style, so I suspect it was already changed from the original round axle style?  Shows no sign of wear - unlike this worm gear.

I have had an offer from Jerry to make a copy or two, so that will be the next order of business.  Should keep us all going until the Parts dept gets new stock.

[armorsmith]

Pardon my confusion here, but how did we get from a demolished worm gear to axle gears? Combination gears are often used in multi-reduction gear trains, and in the case here, are most likely injection molded making them near impossible to directly replace in any other material. As I stated above, two individual gears bonded together, regardless of material is likely the best solution for this application. Both manufacturers mentioned above will custom bore the gears to your specification. To get that number, measure the shaft the gears rotate on in several locations to be sure you get a good measure. Specify the bore in the new gears to be that number, plus .001" minus .000".

Bachmann has not had a good history of re-stocking spare parts, as there is no real profit in spares. In most cases, the spares are run as a part of the production run. The probability of a run of parts for spares is relatively small. Considering the 4-4-0 is a 1:20.3 locomotive that Bachmann has already stated is a scale that no future product will me made, it is for the most part an orphan and I would not hold much hope of help from Bachmann.

Every manufacturer has it's issues with our trains, and most have never addressed them. I do give Bachmann cudos in that every new release of the Big Hauler 10 wheeler chassis, it has been improved to where today it is a very robust product. It appears to me that someone who is willing to take the effort could generate a replacement, but the cost for a small run product will be high.

[Greg Elmassian]

He's talking about 2 different things at the same time:

1. the damaged "dual" worm gear, that contacts the worm on the motor (usually caused by the motor mounting screws loosening or excessive bearing wear in the motor.

2. and some discussion about the axle gear having a D shaped cutout, which seems different from the old style, and apparently NOT the cause of THIS failure.

There was also some confusion about not understanding that the worm gear tooth angle makes it unique from all the other gears in the gearbox, and also some other talk about bypassing some of the gear train.

greg

[Stokerman]

Greg ... many thanks for the news that NWSL will still be a viable resource. I'll definitely sleep better tonight knowing that!

[Fred2179]

but how did we get from a demolished worm gear to axle gears? Combination gears are often used in multi-reduction gear trains, and in the case here, are most likely injection molded making them near impossible to directly replace in any other material.

They are all part of the problematic gear train - I thought the "D" axle was an interesting aside as that is usually the gear that fails, not the worm gear.

I'm not worried about the compound or combination gear.  As you suggest, I can split them in half and pin a new worm gear to the existing spur gear.  [If you look at the exploded view of the new 2017 2-6-0, it's brass gears are pinned to keep them spinning together.]  I have a replacement worm/spur combination on its way from Dave.

Jerry, who makes gears for problem engines, is on Facebook, and has offered to machine one for me. He indicates the angled teeth will not be a problem.

[Fred2179]

Looks like I may have a solution (or two.)  I'll let you know if it works.