Some jobs you know you lack the tools or skill set for. I suspect this is one, although maybe it's simpler to get right than I imagine.
My Sunset HOn3 Rio Grande K-36 recently developed a short while operating. I think I saw the tiny welding going on once. Like many shorts, it didn't seem to stop things at first, then it did.After a lot of inspection and trobleshooting, I found the main driver (the crank axle with attached drive gear) was shorted from side to side. A good cleaning and visual inspection, as well as drawing a pointed tool around the seam between driver and tire in hopes of dislodging any conductor stuck astray in there didn't change matters.
I still have continuity between the treads on both sides -- and no obvious fault to remove or correct. I suspect the brief welding I saw was something that got deep eneough to stick and "spotweld" the driver and tire together.
I have a NWSL Puller and a Quarterer, but not sure they or me are up to the task. Anyone do this who can describe the process enough to give me confidence I can fix this?
More likely would be recommendations for someone who does such a repairs on brass and can return a quartered driver with the gear reinstalled and insulation repaired. It used to be that such services were common in the Classifieds in MR, but no more. Many brass dealers want to avoid repairs, not repair them, but someone must have such skills available?
Mike Lehman
Urbana, IL
Mike:
I'm sure you are up to the task, that is once you know how to do it.
Why not send Howard Zane a PM?
http://cs.trains.com/members/howard-zane/default.aspx
Dave
I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!
Mike,
If you've got the driver set out and the tires are shorted, and the locomotive worked previously, then it would appear that the driver set picked up a bit of metal that caused the short.
There is a good chance that your probing drove the metal "underground".
Assuming the previous is correct, it's still there. Or the short's gone. If it's still there, it would be SOOPAH to find it. I've gotta recommend an intense visual inspection. I wouldn't be shocked if you've already done this. But consider: IT'S STILL THERE.
I recommend spending a good bit of time redoing visual inspection.
IF there's an insulation short, there's a bit of metal doing it. Your task, sir, is to find it. Or not.
Ed
Ed and Dave,
Thanks for the confidence-building, I'm just not sure there's any low-hanging fruit left here. I've been over it several times closely and was careful to do my probing in such a manner it would flick the offending piece out rather than embed it. I haven't taken the connecting rods, etc loose yet to get the driver set out on its own yet.
Even then, gotta remember this is off an outside frame K-36, so there's the big ol' counterweight hanging in the way to the outside of the driver in each side. That's one reason why I was thinking this might require some expert assistance, plus the fact that I don't have a suitable arbor press, just a honking big, sloppy Chinese drill press that is hardly the sort of precision instrument needed to reassemble things.
As mentioned, the short is likely between the wheel and its tire. If it's a bit of metal, it should be obvious under magnification.It could also be caused by the paper insulation between the two parts degrading. I worked on a friend's locomotive which suffered from that, but it was easy to find when the tire fell off as I was inspecting it. That one had the insulated wheels on the opposite side of where they should have been, and the motor was wired to compensate for that.
If you can't find any metal bits between the wheel and the tire, you may be able to correct the problem by applying thin ca to the area between those two parts - place a blob of ca on a smooth surface (glass works well), then dip the tip of an X-Acto #11 blade into it and run the blade around the entire driver (re-filling as necessary) in the slight groove between wheel and tire (the groove is usually more pronounced on the outer face of the driver). Repeat this application on the inner face of the driver, too. This will not likely cure the problem if there's a bit of metal between the driver centre and tire, though.
You may be able to remove the tire from the driver, but that usually involves removing the driver from the axle - not the big deal some think it to be, though. The NWSL Puller is useful for removing the wheel and putting it back on the axle. Removing the tire from the wheel requires some care, as most driver centres are castings and could break when struck. Use a short piece of pipe, standing vertically, to support the tire (with its outside surface face-up) and a slightly smaller pipe or solid rod almost as large as the wheel, carefully centred atop it. Use a small hammer and light, tapping blows on the smaller pipe or rod to dislodge the wheel from the tire. Re-assembly is pretty-much the reverse.With a little care, the driver can be re-quartered visually - I have a NWSL Quarterer, but rarely need it.
Wayne
Wayne,
Thanks, a very useful reminder. I took another stab at this with the sun shining. Went round and round again, finally changed to a pointy new knife blade and that seemed to do the trick after a few more passes. Success! No more continuity.
In these pics you can see why my reluctance to full diassembly before giving up.
Instead of a simple pin into the driver center that most locos have, the outside frame K-classes used this rather more complicated arrangement. The counterweights are pressed onto the knurled axle ends and maintain the quarterling there.
Outside of the counterweights are the connecting rods. Then comes the main rod, which is pinned as a retainer. On the outside is the valve linkage, also pinned in place.
So just getting a puller on square and fair to get things loose is the easy part and that's not so easy. I've got no experience with pulling and resetting those pins on the rod gear, obviously not a job for amateurs or the faint of heart.
In this last pic, you can see the scrapings I managed to extract from the seam where the insualtion sits on one side, but also did the other. The inside fits right against the gearbox, which drops over the gear in the middle. The curves are generally 24" min R, but I do have a 18" R at the end of the freight yard in Silverton. Running through it in the last year or so since that was laid may have caused rubbing and perhaps some small particle to become lodged in the wrong spot, shorting the driver set out.The gearbox frame was something I had to solder to repair a few years back, so it possible could have eroded a bit off a high spot on it, so I smoothed that area with a file.
I never did see the particle, but it may be in the scrapings seen here of the inside pic of the offending driver after it went *poof!* somehow.
I'll put her back together this afternoon. I won't need further assistance here for now, but if anyone knows of a shop or dealer that does this, it could certainly assist others.
mlehman I never did see the particle, but it may be in the scrapings seen here of the inside pic of the offending driver after it went *poof!* somehow.
That word "poof" got me thinkin' of a both wonderful and terrifying possible solution for this kind of problem.
Since the particle of metal is presumably very small (since ya "can't" see it), if you securely clamp a power lead to the insulated driver tire and also one to the axle, and apply enough power, the particle might well evaporate. Solving the problem.
Told ya it was terrifying.
But, being an electrician, I've done things similar to this a number of times. Always by accident, so far.
Mike: glad ya got this problem solved! Even if it was with your own "low tech" method.
I'm glad to see that you've got that problem cleared up, Mike.
Sometimes the hardest part of fixing things is figuring out how to get it apart, in order to get at the problem area.
7j43kTold ya it was terrifying. But, being an electrician, I've done things similar to this a number of times. Always by accident, so far. Mike: glad ya got this problem solved! Even if it was with your own "low tech" method.
Ed,
I'd heard of that, but didn't want to try it unless I was up against the wall. Being small, it might have toasted it, but I also suspect maybe not in this case, since layout power baked it in to start I'm now pretty sure (I noticed the bit of "welding" right after 480 came out of that sharp curve on the north Silverton yard lead.)
Yeah, there's something to be said about just giving it another try, too. I basically had it disassembled as far as I was going unless I got desparate and could get the blade tip in on each side of the driver to scrape. I was concerned about driving something in even deeper, as Ed suggested, or worse that I would break the tip of the new blade off in the insulation seam (although I'm pretty sure I could at least see where that was.)
And I was really concerned that if I got all the pretty tomfoolery of rods apart I'd never get it back together.
Part B of this drama might be vacuuming your tracks. A magnet would be good, too. But there's also non-magnetic metal bits out there bent (yuk,yuk) on destruction.
Your mention of a sharp curve (as in abrasion) gives a possible starting point.
I didn't followup sooner, because there was nothing except more frustration. Went through gouging out whatever was in the insulation seam about a dozen times. I even gave up for a couple of days, as I wrote Bear, because I wasn't getting anything productive done and figured it needed a rest. I spent another 3 hours with it this evening, but can report that I did manage to get it going at last. It still needs some tuneup, as all the handling wasn't good for it. I even mangled on of the valve gear links, so will have to fab a new one, although runs OK as is.
This. like electroconvulsive shock therapy, required the patient endure several grueling session under the electrodes. It wasn't pretty and it was just a little dangerous, considering I didn't bother to remove the Tsunami. Either dumb luck or cunning saved me there.
7j43kPart B of this drama might be vacuuming your tracks.
They're actually pretty clean and I do go over them with a magnet from time to time. Based on how it went and what I could see of it, the offeding particle was likely a chunk of brass, so a magnet wouldn't help much with it.
I suspect the gear box rubs on the driver sometimes and that's how I picked this up. I was think I need a piece of styrene laminated on either side, but it needs to be thin.. but then would rub through again too easily. Then it came to me...I can use that protective film people put over their cell phone face, as I even have some extras around to cut from...hmmm.
After all of that, Mike, you deserve two:
Yeah, I needed a drink (which I mostly don't anymore), so downed a Fin du Monde PDQ and things seemed to go better after that, even though I set it all aside for a couple of days at that point. She's tuned and running better than ever after a few more hours work lst night/early this morning. I'll post pics when some touch-up, etc is done .
BTW, I did apply the Zagg film to the sides of the gearbox and that seemed to work well. Seemed to self-stick, even without water to squeegee over it, so left it like that.
And I think I deserve another Fin du Monde...
Many years back, Roy Brakmann, who at the time was one of the best brass mechanics in our area swore he had the perfect fix for driver shorts. He fixed an LMB NYC H10 for me using his method which was pouring a small amount of CAA glue around the inner rim of bad driver and immediately hitting it with accelerator. I tried this same method on another LMB import, but wound up glueing the driver and axel to the frame. Roy managed to fix this loco for me using debonder and then his method. I've only seen results, but have never successfully done this, but if all else fails, perhaps it is worth a try.
HZ
Howard,
Thanks for the suggestion. I'll file it for future reference. I cleaned itmultiple times and I think after the second time I made the short go away, I applied CA hoping to lock things in place. This seemed to backfire, as after chasing the bug away, when I put the loco back on the track darn thing was shorted again. Guess I should've tried the accelerator? In any case, yes, there was a moment when I thought I was going to glue the whole mess together. My emergency can of acetone is handy nearby...
I finally grabbed a few pictures now that #480 is back in operation and running quite reliably.
In this pic you can see the considerable extra heft of the K-36 vs the C-19. The former can pull 13 cars up the the rulling grade between Durango and Silverton, while the C-19 can lift only 4.
mlehmanI finally grabbed a few pictures now that #480 is back in operation and running quite reliably.
Running properly and lookin' good!
What's the box-like apparatus sticking out the side of the smokebox?
Thanks, Wayne.
doctorwayneWhat's the box-like apparatus sticking out the side of the smokebox?
You know, I'm not really sure. I remember asking that very same question years ago and getting several answers that didn't really agree. Since it's big enough to put a couple of lunchboxes in, maybe a food warmer?
The Sunset K-36 (and IIRC, the K-28, too) has a partially enclosed brass gearbox that the motor mounts to. The worm output drives a standard spur gear that engages the gear on the 3rd driver. The sides of the gearbox enclosed it, but it's open to the bottom where it fits down over the top of the driver, where the spur gear then rests on the driver gear.
Yep, definitely rubbing the gearbox is where this came from, although the pics show it in the middle of me making more fine filings. As I noted, this thing runs down to 18" min R, but at a price. I noted that I'd repaired the gearbox when one of its solder joints came apart and the roughness of this repair had caused a little rubbing. Smoothed that with a file, but the bigger issue of the gearbox remained.
Applying the Zagg film on both sides where the driver might come into contact with the gearbox definitely helped. You really can't shim it out to prevent all contact, as the sliding back and forth is needed for the loco to traverse curves easily.
mlehman mlehman wrote the following post 2 years ago: 7j43k Told ya it was terrifying. But, being an electrician, I've done things similar to this a number of times. Always by accident, so far. Mike: glad ya got this problem solved! Even if it was with your own "low tech" method. Ed, I'd heard of that, but didn't want to try it unless I was up against the wall. Being small, it might have toasted it, but I also suspect maybe not in this case, since layout power baked it in to start I'm now pretty sure (I noticed the bit of "welding" right after 480 came out of that sharp curve on the north Silverton yard lead.)
Ed, I'd heard of that, but didn't want to try it unless I was up against the wall. Being small, it might have toasted it, but I also suspect maybe not in this case, since layout power baked it in to start I'm now pretty sure (I noticed the bit of "welding" right after 480 came out of that sharp curve on the north Silverton yard lead.)
A couple of months back, the 480 came up lame again. After thorough trouble-shooting, I determined I was again experiencing an insulation failure on that 3rd driver. This time I took to the brute force method - zap it! First I tried with a DC train transformer. I took a pair of alligator-clip leads. I formed a short probe from Tichy phosphorbronze wire and clipped it in one lead and touched the other clip to the driver tire. Gave a brief pop, but ultimately didn't solve the problem.
Like Dr. Frankenstein, I figured I just needed more amperage. With the help of some assistance to make sure I didn't get any leads crossed, I went in for a big zap from the Land Cruiser with the jumper cables, still using the small leads off the transfomer for the final connection, because the jumper cable clamps were just a wee bit too big in HO scale. Pretty good sized pop and the deed was done. Sure enough, the driver center was isolated from the tire. Hooray! Got it back on the track and she ran fine.
Gutsy move! Even though pretty logical, still had to make you a little nervous, no?
Dan
Yep, the theory said it's OK, but it was somewhat nervewracking. I figured the small probe I made from the Tichy wire on the black/ground side of things would act as a fusible link in case things got out of hand.