Not one to back down from a challenge, I figured I’d try the collar repair before plan B, which was to develop 3d printed replacement gears. This whole thing has been a stupid distraction, but I digress.
All 5 axle gears are cracked in my example. This one includes the replacement non traction tire axle too. It’s from the first run. If you are looking to quickly inspect a model in box, just look at the spare axle and see if it’s cracked.
I lucked into some perfect repair material from Amazon… I just searched up “2.8 mm ID tube”. It’s stainless, so it’s harder to work than brass, but the dimensions were perfect spec for the requirement.
This repair was not easy!
Peteski is correct about this mechanism; you need to time the driver gearing too. If don’t, the gearing will move the drivers out of relative position to each other even if they are in perfect quarter. I had to figure that out the hard way. This isn’t my first steam rodeo by any stretch, but it’s the first time I’ve dealt with geared drivers.
The worm however is connected the front 1-2 driver set, not the 3-4 driver set, despite the #4 being the traction tire driver.
To make things even more complex, the driver axles are indeed splined. Not only do the drivers need to be in quarter they need to be in time with the gearing too. And you can’t just tweak the driver on the axle to adjust this as they are splined, so any adjustment is a complete removal of the wheel. I wasn’t willing to play games with enlarged rod holes, that’s just asking for trouble you can’t fix later.
It took me two attempts. I first applied a collar on the long side only.. the gear is offset, and it didn’t seem necessary to collar both sides, considering how little room there is on the short side. The collars fit is absolutely perfect, very tight. I got them started in my vice, and then used peteski’s method of using a pin vice to push the collar up to the gear. I chamfered the end of the gears slightly with a file to help get the collars started, and I made sure the collars were burr free after cutting them.
In the first attempt I left the rod pins in on the first two drivers, as I figured they get looser with every removal. After some frustration around the gear timing, I ended up making sure all of the gears were properly aligned to the fireman’s side drivers by way of the slot marking on gear. And then quarter from there. The backside of the wheel structure has 4 spokes that connect the metal tire to the axle, which are very helpful to index the whole thing.
After getting everything timed and back together, it still thumped. It was a little better, but not fixed. Ughhh.
So I tore things down more substantially, and checked for gear problems upstream of the drivers.. but not surprisingly found all was good. I then just tested the drivers one set at a time, with all of the rods completely removed.
Two drivers were fine, and two were not. The main driver (#3) and the #1 were still thumping. I added a thin collar on the short side, and that made the difference. I added the thin collar to the #2 driver preventatively, but didn’t bother on the removable #4 as it’s easily serviced.
Gear timing/quartering is easier done with the rods removed. Put all of the wheelsets in and make sure the holes are perfectly aligned on both sides. I only had one out of time just a hint on one side when reassembling the second time in this fashion although fixing that one was a pain… with the two collars the wheels are very difficult to pull apart, and of course the wheel I didn’t want to come out did.
No more thumping. The additional collars on the short side do restrict the lateral motion of the drivers, but it still has no trouble with my 9 3/4 hard S bend coupler torture test loop so it’s not a problem, or at least with 3 of 4 drivers with short side collars. I had to gauge the wheels a tad tighter then I like (still just a hint of play in the NMRA gauge but I like things set right in the middle) to make sure the bearing blocks stay in position properly, another learning from attempt 1. If you fully press the wheelsets on the gears you end up under gauge.
Its totally repairable. But not without a fair bit of effort and attention to detail. On spookshow's site there is mention that the 0-8-0 tooling is lost. It’s a model not without flaws, but in terms of the sophistication and attention to detail I was impressed. No very ugly solid drivers or massively oversized plain rods like seen in so much other n scale steam. It’s worthy of the repair effort.
Now it’s fixed I need to get to dealing with the MASSIVE tender - loco gap wiring disaster. But for now, it’s going back to sleep in its box, I have couplers to deal with.
Some show and tell, but by no means a tutorial:
1st Attempt.. Note the splines.
Gear and collars
I figured this was going to be success!! WRONG. Fail, still thumps.
Thin collar added...
Note the slot in the gear...SUPER useful for indexing the gears. The metal tire/hub spokes are also super helpful for the indexing.
This is success! No more thumping!
