Author Topic: Precision Scale PRR K4 4-6-2 Repair Tutorial  (Read 1533 times)

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mmagliaro

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Precision Scale PRR K4 4-6-2 Repair Tutorial
« on: July 29, 2014, 11:45:48 PM »
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Maybe these photos will save some of these from the junk pile.  Having fixed a number of them with good results, I feel reasonably confident about sharing these ideas.  I don't think any of this is radical or new.  I know that Marc and Hans Starmans, and Victor Miranda, repair these brass K4's with good results.  The Starmans' even wrote a nice article on the subject for the NTrak Steam Locomotive Book Addendum.

But in any event, I hope these are helpful.

You need steady hands, jewelers screwdrivers, small files, a wheel puller. good soldering skills, and ... well ... a little nerve.   After all, we're playing around with an engine that goes for $500 these days.

I apologize for some of the typos I noticed in the embedded text after I posted these.

The photo text should explain what's going on.
















« Last Edit: July 02, 2017, 12:48:50 PM by mmagliaro »

peteski

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Re: Precision Scale PRR K4 4-6-2 Repair Tutorial
« Reply #1 on: July 29, 2014, 11:55:33 PM »
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Excellent tips (as usual)!
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victor miranda

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Re: Precision Scale PRR K4 4-6-2 Repair Tutorial
« Reply #2 on: July 30, 2014, 02:11:29 AM »
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Hi Max,

I truly cringe when I read your advice to grind the corners of the steam chests.

any chance I can get you to reach for plastic wheels or wheelsets?

where'd you get the slat pilot k4?
 the bay usually has lumpy cast steel pilots

victor



mmagliaro

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Re: Precision Scale PRR K4 4-6-2 Repair Tutorial
« Reply #3 on: July 30, 2014, 03:53:44 AM »
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I always cringe at having to modify detail on a brass locomotive.  But the practical matter of making it
run trumps keeping all the details intact.  Plastic wheelsets might work, but only so far as not causing a short.
They would still touch, drag, and start causing derail problems.

This isn't one of mine.  This is a repair for someone else, so I have no idea how he came by it.

The rear coupler is another "detail" problem.  The way the brass piping detail is placed, it gets in the way
of the coupler operation.  One has little choice by to bend some of that out of the way.
(On some of these, those pipes are missing already, probably because they broke off or people were trying
to move them out of the way).

So yeah... would like to not do it, but it's either that or tell people they need 24" radius curves.
I know on my 18" curves, those wheels hit and rub often unless I make some room.  Plastic fixes the shorts, but even with
washers to limit the motion, there's still rubbing going on.



Norway2112

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Re: Precision Scale PRR K4 4-6-2 Repair Tutorial
« Reply #4 on: July 30, 2014, 10:15:48 AM »
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where'd you get the slat pilot k4?
 the bay usually has lumpy cast steel pilots

victor

Victor,

It appears that this is the engine I recently sold on ebay to a guy in CA.  He mentioned he was sending it off to get a  "tune up" as it had been in storage from an estate for years.  I had a sneaky suspicion I knew who the "tuner" would be.  Glad to see Max giving the engine a new life!  I remember thinking it was gorgeous when I took photos of it, appeared to never have been run, but was very typical of PSC K4's in running quality.

Phillip

mmagliaro

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Re: Precision Scale PRR K4 4-6-2 Repair Tutorial
« Reply #5 on: July 30, 2014, 12:46:01 PM »
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The buyer asked me about the possibility of a working front coupler for double-heading.  That slat pilot
was one of the reasons I said, "No".   Sure, it could be done.  But to drill and file out a hole big enough
for even a Z Scale MT coupler box would just ruin that pilot.  Compared to the tiny dummy coupler that is
cast on there, it would become painfully obvious just how oversized our coupler boxes and couplers are, even in Z.

And the pilot is right out front and center, so it would really show (unlike my hacking of the underside edges of the steam
chests, which you really cannot see when the engine is on the track, especially if you touch them up with a little black paint).

Speaking of black, what's up with the "green" color on these things?   It suddenly dawned on me how overtly green they are.
PRR "DGLE" is still an almost-black color with a greenish hue that you can only see in certain light.  These things are, well, green.

timwatson

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Re: Precision Scale PRR K4 4-6-2 Repair Tutorial
« Reply #6 on: July 30, 2014, 04:40:59 PM »
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re: The steam chest grinding.

Try liquid electrical tape. Black. I've used it on Kato mikados that had their rear truck shorting on the frame and it works well. Do 2 coats and it will be insulated.
Tim Watson

My pics: http://www.flickr.com/photos/nscalerail/sets/

Modeling a version of the Jay Street Connecting RR. in Brooklyn.

spookshow

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Re: Precision Scale PRR K4 4-6-2 Repair Tutorial
« Reply #7 on: July 30, 2014, 04:58:06 PM »
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re: The steam chest grinding.

Try liquid electrical tape. Black. I've used it on Kato mikados that had their rear truck shorting on the frame and it works well. Do 2 coats and it will be insulated.

re: what Max already said -

It's not just a short-circuit problem. The wheels would still touch, drag, and start causing derail problems.

Cheers,
-Mark


timwatson

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Re: Precision Scale PRR K4 4-6-2 Repair Tutorial
« Reply #8 on: July 30, 2014, 05:07:17 PM »
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Just adding some other tips.
Tim Watson

My pics: http://www.flickr.com/photos/nscalerail/sets/

Modeling a version of the Jay Street Connecting RR. in Brooklyn.

mmagliaro

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Re: Precision Scale PRR K4 4-6-2 Repair Tutorial
« Reply #9 on: July 30, 2014, 07:50:23 PM »
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Tim, Mark, Victor, and all...

Yes, it's partly mechanical, not just about shorts.   That's also why I cut away the steam chest a little on both sides,
not just the side that shorts.  I should also mention that not only do the wheels touch, but the frame of
the pilot truck itself can touch too.

Gentlemen, there is more than one way to correct this.  I definitely welcome the commentary and opinions.
It's a matter of what your preferences teaches you over time.   I have tried using plastic wheels and coatings
for this issue on other engines  (a Bachmann "J" comes to mind at the moment), and I wasn't happy with that approach.
Also, having a trailing truck touch a little is not as troublesome as the pilot truck.  99% of the time, the trailing truck
is being dragged along behind and it will not lift up.  The pilot truck is always being pushed through curves, and it
always seems to find a way to lift up if you give it any excuse (like hitting the steam chest)

I am doing what my experience has taught me is a safe, sturdy, and reliable way to make sure
the wheels don't short or derail.   

timwatson

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Re: Precision Scale PRR K4 4-6-2 Repair Tutorial
« Reply #10 on: July 30, 2014, 08:25:12 PM »
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Makes total sense man. Pushing is always harder on our locos than pulling, it seems. As always, these are great tips, thanks for continuing to share them.
Tim Watson

My pics: http://www.flickr.com/photos/nscalerail/sets/

Modeling a version of the Jay Street Connecting RR. in Brooklyn.

victor miranda

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Re: Precision Scale PRR K4 4-6-2 Repair Tutorial
« Reply #11 on: July 30, 2014, 10:32:32 PM »
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forumers,

sometimes I think what I wanted to say did not come across as what I wanted to say...

I start by letting you know that what Max said is correct.
If you want reliable operations from a pilot truck...
you have to clear the truck.  there is no skirting the issue.
 
If you are ever building from scratch...
move the cylinders out, make them a little smaller and
use the thinnest wheel treads you dare.
oh and make the truck as heavy as you can.

Now try all that on a brass loco.
You will most likely grind the inside corners  of the steamchest
because the other options are not really on the table.

I know this.  I still don't like it...

.... that or get used to wide curves and long turnouts.

victor




 
 

mmagliaro

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Re: Precision Scale PRR K4 4-6-2 Repair Tutorial
« Reply #12 on: July 30, 2014, 11:55:31 PM »
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Yes, yes, and yes.... regarding Victor's points.
We're fixing a brass engine, and we make choices.

When I build my own engines, I don't have to grind the steam chest and I am even able to get a Z coupler on the front and
still make the pilot truck work.  Why?  Not because I'm some kind of genius, but because I plan on that from the beginning
when I am making the parts.

Once the pilot, truck, etc are cast in brass (ha ha) it's not so easy to change the way it works, so I choose to come down
on the side of functional stability over costmetic appearance, if I have to be forced to choose to between the two.

I am thankful for everyone's comments and questioning of how I did what I did.  I hope nobody feels like I don't like the debate.
It's good for everybody.


eric220

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Re: Precision Scale PRR K4 4-6-2 Repair Tutorial
« Reply #13 on: July 31, 2014, 12:38:47 AM »
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It appears that this is the engine I recently sold on ebay to a guy in CA.

Yo! :D

Can't wait to get her back!
-Eric

Modeling a transcontinental PRR
http://www.pennsylvania-railroad.com

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Re: Precision Scale PRR K4 4-6-2 Repair Tutorial
« Reply #14 on: July 31, 2014, 01:42:57 PM »
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I knew it had to be Eric!
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