One of my converted to narrowgauge Kato HO NW2 locos has developed a problem where it only drives one axle. Everything seems normal with the worm gear at the affected end. It's driven by a very short shaft that has a cross-shaped fitting on one end. This mates with a black plastic coupler in a recess in the end of the flywheel on that end of the motor. The plastic coupler then also mates with a corresponding cross-shaped piece of white plastic recess inside the end of the flywheel.
The black plastic coupler looks OK. I suspect the white plastic part it mounts to is slipping on the driveshaft.Does that sound right or is there something I'm missing there?
I've been thinking about squeezing some CA into the recess where it can lock lock the white plastic fitting to the drivehsaft/flywheel. Is that advisable or is there another solution?
Mike Lehman
Urbana, IL
I would be extremely leery of putting any type of adhesive such as CA into the flywheel -- my choice, if anything at all, would be a small dab of Goop which could be cleaned out later if it proves to be the wrong solutin.
Yeah, that was one concern. However, the parts (white plastic cross-shapped fitting and the shaft stub it press onto) are so small that I'm not sure anything but CA will get enough grip to overcome the torque of the motor.
I can pull the white fitting out easily enough, so I can daub the CA into the shaft recess in its middle. Keeping it neat should work. If it fails, then it's loose again, so really won't lose any ground.
If I could get at the shft stub to knurl it some, I'd do that, but no way to do that without pulling the flywheel, then reinstalling would likely scrub off the raised parts of the knurling, so no net gain.
Thanks for the suggestion, though. Anyone else?
Have you determined that it is indeed just spinning instead of turning the coupling? Run it with the shell off and see what's going on. With no load it may all spin as it should, then you can check down the drive line by briefly holding various parts and applying power. It could be internal in the truck, or maybe somehign just got jammed in the gears and stopped it from turning, which then shows up as the coupling spinning on the motor shaft because that was the weakest link in the chain.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
mlehmanThe black plastic coupler looks OK. I suspect the white plastic part it mounts to is slipping on the driveshaft.Does that sound right or is there something I'm missing there?
If you can remove the white plastic thingy, use some epoxy on the drive shaft and reinstall the thingy. I would recommend epoxy because of the 5 minut setting time giving you plenty of time to position everything
Jay
C-415 Build: https://imageshack.com/a/tShC/1
Other builds: https://imageshack.com/my/albums
Randy,
Oh yeah, it's just spinning. I got it out pretty easily by grabbing it with the tweezers and it came right off. I was thinking maybe the factory used CA, but no signs of that, so I suspect just a press fit.
No viewing in action without the shell on with the Kato. I's made like a N gauge loco, with two heavy halves that enclose the motor and drivetrain. That's what makes them outstanding switchers on the layout, as well as very potent narrowgauge road power when I convert them to my NW2M configuration. But you can't run it when you can see it, because it's all in pieces then.
modelmaker51If you can remove the white plastic thingy, use some epoxy on the drive shaft and reinstall the thingy. I would recommend epoxy because of the 5 minut setting time giving you plenty of time to position everything
Jay,
Epoxy may be better for that reason, plus a little more controllable. It may also stick better since the white plastic fitting is engineering plastic I suspect. I'm going to try that and let it sit until my next break, then reassemble and test.
Morning Mike,
Make sure your fix is real neat and tidy, you don't want to create an "out of balance" situation.
Good luck with that fix.
Johnboy out...............
from Saskatchewan, in the Great White North..
We have met the enemy, and he is us............ (Pogo)
Most likely this was just pressed on. Replacement parts may be available, a fresh one might fit tightly. Epoxy should work, just a tiny dab in the hole and press it on, then wipe off any that oozes out to prevent it from sticking to the wrong thing and also to prevent out of balance conditions as mentioned by Johnboy. At the motor RPM, it doesn't take much to result in an annoying buzz or vibration when running.
Didn;t realize this was enclosed like an N scale loco, the Kato locos I've dealt with have all been RS and RSC, the ones made for Atlas, and they have a more typical for HO exposed drive (once you take off the weight slugs, which just sit over the gearboxes and aren't even screwed in).
Johnboy,
Good point on making it neat and balanced. Fortunately, the thingee had a center relief hole where it pressed on over the shaft, so pretty easy to clean up the excess and leave it neat and balanced. Plus any off-balance will be near the shaft's center, so effects would be minimal.
rrinkerMost likely this was just pressed on. Replacement parts may be available, a fresh one might fit tightly.
Yeah, not sure it is available. There is something called the "end middle joint" (honest, not trying for cheap laughs here. ) which might be either it or the flexible black plastic coupler that goess between the two-cross shaped fittings, the one I glued and the one on the worm drive.
rrinkerDidn;t realize this was enclosed like an N scale loco, the Kato locos I've dealt with have all been RS and RSC, the ones made for Atlas
"Split-frame" is I think the technical term. IIRC, the NW2 was the first one done that way in HO. Not sure about other diesels, but I think that's how Blackstone does its HOn3 steamers, too.
Not sure why it hasn't been more widely adapted (or maybe it has and I'm just not buying it)? Definitely makes for a heavy loco, but it's heck to squeeze a decoder in unless accommodation is made for it (as is likely the case with more recent projects that use split-frames.)
Oh, yeah, this fixed it. She's running again, just need to square up one of the drive wheels and reset it to take the lope outta her step.
Bachmann makes diesels like that as well, although at least for the longer ones they don't runt he metal all the way to the top of the shell, leaving room for a circuit board or decoder on top. No speaker space though. They also tend to suspend the whole thing over the trucks by a pivot way up on the top of the frame, which makes them wobbly.
Seems overkill except for small switchers. My Bowser Baldwin switchers are not built like this, yet pull pretty well. They also have taller hoods than the NW/SW switchers, so more room for weight even though thy are rather small. Larger diesel locos already pull far more cars than the equivalent prototype in most cases, and that's without traction tires, so making them even heavier isn't really going to add much to the experience.
I was thinking along the lines of the various switchers released with sound nowadays, yet which seem to have limited tractive effort because of conventional chassis design with the speaker taking up part of the room formerly used for weights in such models. They could use a whole new split-frame chassis to advanatage, but I understand the money may not be there for such a wholesale redesign.
There's also the advantage that the drivetrain itself is fully enclosed down to the bottom of the trucks. That tends to keep cruff out of things, somewhat compensating for the disadvanatge that it does make visual diagnosis difficult.
In the case of this loco, still didn't save it from the evils of foam ingestion because of the small openings in the bottom cover on the trucks for the drive gears. Digging that out was where this whole project started.