Large Scale Central

Bach 4-4-0

Problem Solving
#1

This is the second newest release 4-4-0 I’ve had in for axle gear issues. Eureka and Palisades.
Black gear (and lower tooth count…not a 2-8-0 count) instead of white.
I thought the first one was an aberration, but it ain’t.
They have done something with the molds for the drivers. You need 4 different tools and six hands to get the journal box off the wheel.
I checked with a dial caliper, the taper is astounding.
.005" to .006" from back of the wheel to the end.
Twisted some emery around the stub and worked it until the silly thing went in and out of the bushing in the journal box as it should.
Can’t be good for operation. In fact, the journal bushing was locked so hard on the right side, the bushing was turning in the plastic box.

I’ve done a LOT of gears on 2-8-0’s and the 4-4-0/2-6-0 series. NWSL never has gotten the instructions up to date, even though I’ve talked to them and sent drawings as requested.
You need about a .030" shim on each side of the gear. The Bach gear has a wide hub…the NWSL has no hub at all.
My nylon shims are .035", so, using the same emery paper, worked them down to .030", made sure there was “rattle” in the axle before putting valve gear and wheels on.

Who’s gonna be the first to label this as “bashing”?

#2

I talked to a dealer today that mentioned the latest brass gear from Bachmann for the Connie (2-8-0) has shoulders.

The original one did not and would let the bushings fall into the bottom gear case leaving the axle to wobble. I added an Aristo-Craft FA-1 axle washer on each side of the gear to keep the bushings from falling in.

The NWSL gear for the Connie does not have the proper center bore. After watching a friend pound the end of the axle crooked in an attempt to get the gear on, I drilled it out with a 1/4 inch bit and tapped it on with a deep socket and rubber mallet.

#3

I use some spacers (automotive) and my bench vice. They press right on both the 4-4-0/2-6-0 and 2-8-0. Both styles of gearbox need shims.
I had a guy bring in a 2-8-0 a while back with a NWSL gear…no spacers…and the gearbox went one way, axle the other, and chewed the side of the gears clean off.
It ain’t rocket science.
I even offerred to mail an entire gearbox to them…I can provide several of each.
No reply.

#4

Dave, is the black gear the same profile as the older white (2-8-0) gear? Was it also broken, or was this a PM thing?

And if I’m reading your post correctly, the wheel casting itself (the “axle” so to speak) that goes into the brass bushing has a taper on it that’s causing it to get stuck in the brass bushing? (i.e, the “axle” gets wider than the bushing as it gets closer to the back of the wheel?)

Later,

K

#5

Same profile. Snapped clean through. In fact, usually white ones get 2-4 cracks, of which one eventually radiates in a small crack, since some of the stresses are relieved in the other smaller cracks. This one appears to be one BIG crack.

#6

Have you tried putting a sleeve on the hub of the Bachmann gear, a la the “fix” for USA’s split hubs? I’ve not tried it installed on a locomotive, but I did at one point slice some 3/8" brass tubing (I forget if that’s ID or OD at the moment) and it was a good, snug fit. Next time I have one cross my bench, I may give that a go to see if that works. (Can’t be any worse, eh?)

Later,

K

#7

Won’t work. The issue is the plastic shrinks, and continues to do so from the day built. Yes, you can stop the cracks from growing at the hub, but the rest of the plastic gear continues to shrink and it will pop. For the amount of work involved to take a 4-4-0/2-6-0 apart to sleeve, and have to replace the gear anyway at some point, is an effort in futility.
If it goes, just do a machined delrin first time and be done with it forever.
The issue with the older USA stuff was Sanda Kan changed one of the specs (axle diameter or internal gear diameter) without either telling USA or addressing the mating part.
Those cracks are from stress of a too big axle or too small gear.
I don’t think…quick memory bank check…I’ve seen a USA gear split through the gear teeth.
Of course, the issue would be they get changed when the wheels fall out.