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HO scale PFM N&W Class S1a 0-8-0, short in second drivers

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HO scale PFM N&W Class S1a 0-8-0, short in second drivers
Posted by tsutsu1218 on Sunday, August 28, 2016 11:36 AM

I have a brass HO scale PFM N&W Class S1a 0-8-0 that has developed a short between the wheels of both sides of the second driver from the front. Is there any suggestion as to what caused this? And are there fixes and/or replacement drivers for this set? Thanks!

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Posted by rrebell on Sunday, August 28, 2016 12:18 PM

One of the old fixes was to dig out the old resin infused insulating paper or whatever that stuff was a bit at a time replacing it with epoxy. They did it a bit at a time so that the hub remained in the same place exactly.

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Posted by doctorwayne on Sunday, August 28, 2016 12:48 PM

I had the same problem with a couple of B&O 0-8-0s that I was working on for a friend.  It didn't help that one of them had the drivers reversed, side-to-side, either.  On the other one, the tires on the insulated side were falling off the drivers.

With the drivers, complete with rods and valve gear attached, removed from the loco, I placed them on their side, with the insulated drivers facing up, then applied watery-type ca all around the joint between the wheel centre and the tire.  This fixes the two parts together, but also flows into any small gaps where the paper insulation may be too thin or missing.

If the tires on the other side become loose, you can use a similar fix, but don't use more than a very small amount at 3 or 4 places - just enough to make a connection at those points, but not enough to flow and create a fully-insulated wheel. 
Don't despair if that happens, though, as you can always add wipers to rub on the backs of the tires. Stick out tongue

Before painting steam locomotives, everything but the motor gets cleaned, and, as a final step, a bath in hot water and dish detergent, followed by a thorough rinse.  Locomotive drivers get the same, but it's a quick swish in the soapy water and a fast rinse, to prevent damage to those paper insulators.  Everything else can soak for a while.

EDIT:  Here's a LINK showing the installation of all-wheel pick-up on one of those locomotives.

Wayne

 

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Posted by mlehman on Sunday, August 28, 2016 1:21 PM

You've probably already checked that the problem is isolated to the driver, but worth mentioning as a general check in situation like this is to verify a brake shoe or other detailing part is not touching the driver.

Mike Lehman

Urbana, IL

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Posted by 7j43k on Sunday, August 28, 2016 2:58 PM

tsutsu1218

I have a brass HO scale PFM N&W Class S1a 0-8-0 that has developed a short between the wheels of both sides of the second driver from the front. Is there any suggestion as to what caused this? And are there fixes and/or replacement drivers for this set? Thanks!

 

As already mentioned, make sure the driver pair is not installed "backwards".  PFM DID ship product that way; I ran into a PFM NP 0-6-0 with the problem.  And it's pretty obvious they didn't test run that one.  Since it wouldn't.  Run.

If it "developed" a short, as in it used to be OK, as also already mentioned, make sure it's not the brake rigging.  Or some other bit of meandering piping.  Also inspect the side rods and check for contact with the insulated tire.  THAT shouldn't happen.  But if it did.......

If the above doesn't solve it, and especially if the short is happening with the driver pair out of the locomotive, you surely do have a "short between the wheels".  So the insulation has been bridged at some point.  In that case I would get my high powered magnifying glass and do a visual inspection of the insulation.  You will likely find something metallic.  Remove it.

 

You've been supplied with a pretty good set of logic tools in this topic.

 

Let us know how this works out.  

 

 

 

Ed

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Posted by 7j43k on Sunday, August 28, 2016 3:01 PM

rrebell

One of the old fixes was to dig out the old resin infused insulating paper or whatever that stuff was a bit at a time replacing it with epoxy. They did it a bit at a time so that the hub remained in the same place exactly.

 

 

Unless the tire is falling off the wheel, I don't see how the old insulation could "short" without the help of some bit of metal.  Which should be removed.

Also, rather than dig out the old stuff (if that were to prove necessary), it might work to impregnate it with liquid epoxy, wicking it in with a brush.  I've got some of the stuff here, and it can be mighty useful.

 

Ed

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Posted by tsutsu1218 on Monday, August 29, 2016 9:46 AM

Thanks for the quick replies. I have since removed the driver retainer, and discovered a very small piece of metal, less than half the size of the dot of this sentence, bridging the gap between the insulated driver tire and the driver center. Very hard to see without a magnifier and good lighting. I removed it, tested the driver pair again, and seems to have solved the short. 

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Posted by 7j43k on Monday, August 29, 2016 9:59 AM

Hooray!

 

A person could wonder where that bit of metal came from.  And whether there was more of it that might again cause a problem.

Might be a good idea to "slide" a magnet over your trackwork.

 

Ed

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Posted by dinwitty on Monday, August 29, 2016 2:44 PM
during operation a shred of metal could have sprayed out, hit the driver, shorted and welded itself to the rim/driver. It may not be so strange for this to happen when running an engine, if you built a Bowser steam or MDC engine you -run in- the engine, this would wear in the working metals to make smooth contact surfaces but may shred off some metals. Lube your engine up including siderods piston rods any moving surface against metal/metal.whatever. Ii had a rim fall off my 0-10-2, somewhere I heard mentioned using Gorilla glue to put it back on as it expanded when set, you want that on the drivers to tighten up the seal, works great. I like that idea of selectively reaming out the old insulation/glue in, that would work keeping the rim in place, you could hollow out small quarters areas, glue it, hollow the rest then glue.

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