PRR D16sb research for a build

[wm3798]

Those are the engines that held court on Delmarva into the 1940s.  Or very much like them.  The sun gradually set on them as bigger PRR steam was demoted from the mains to the hinterlands in the late 40s and 50s.

Lee

[Ed Kapuscinski]

Speaking of the hotness. I don't know any red blooded American who can see this and not get the vapors.

[dougnelson]

Where and when was this excursion?  Jointed rail under catenary??

Speaking of the hotness. I don't know any red blooded American who can see this and not get the vapors.

/>

[peteski]

Speaking of the hotness. I don't know any red blooded American who can see this and not get the vapors.

Or a vapor lock! 

[randgust]

A milestone - I think - I hope....

After two false starts, I successfully mounted a Rivarossi driver on the Bachmann axle, and murderously carved up the Bachmann frame/boiler to clear 68" drivers.  And it's actually cocentric, and it spins nicely.   That 'should mean' that I can use Bachmann side rods and original gears and get this thing quartered up properly.  And hopefully turn the flanges down a bit, although I really don't need to for my own use.

Until I get the four drivers, worm, and rods working smoothly for this Frankensteam I'm trying not to get distracted by other details.

It's very much a Sid project from Toy story, when I'm buzzing out big chunks of a Bachmann boiler with the Dremel to clear bigger drivers.
http://www.cornel1801.com/disney/Toy-Story-1995/pictures/53.jpg

[Ed Kapuscinski]

Where and when was this excursion?  Jointed rail under catenary??

Whoa, you don't know about those excursions from the 80s?

There were a couple. They were amazing.

[randgust]

OK, well, I'm stalled for a bit.

I got the Rivarossi main drivers on the Bachmann axle flanges turned and quartered, and then discovered I'm missing more parts from my junker Bachmann 4-4-0 than I thought, and it's kind of a killer until I get them.

This was an old one - the original Hong Kong run - with the thicker hex-nut universal shaft and the metal gears.  That shaft is missing.    I'm also missing the screw that holds the bottom plate to the worm shaft bearing block between the two worms.   And I'd taken the main drive rods (crosshead to driver) out for the Climax B project, so I am missing those as well.    Those would come in handy I think, although it's looking like the Rivarossi cylinders and crosshead may work with some modification.

As I'm using the Bachmann frame, the Bachmann side rods (driver to driver) fit precisely, and even fit well over the Rivarossi bushings.

But for lack of that screw, and the universal shaft end (which I intend to remount to an NWSL universal shaft back to my gearhead motor) I'm stopped.   Bachmann doesn't have the parts, and I'm watching on auction sites for any 'nonworking junkers' with the right parts.

So I'll ask here as well if anybody has a junker that I can get for parts.    I'll find some eventually as junkers show up, but I was making pretty good progress until this issue came up.

[Lemosteam]

I see them all the time on Facebook N Scale selling groups.  I may be able to broker one for you if you don't FB.

[randgust]

Parts on the way.... from another Railwire member.   Good thing because it's a real crapshoot out there finding the right generation of the mechanisms when I've already started this using the oldest one.

And as I was digging around in my ample box of surplus body shell parts (maybe the missing driveshaft was in the bottom??) I found something else I knew I had somewhere but couldn't find... two nice resin copies of the Trix B6 boiler casting.  It really looks like that cab could be shortened to the proper size.

I got them from somebody off the forum in trade for something else, and my pack rat mentality dating back to my teenage years is once again justified.

[randgust]

Quick update - NickelPlate759 (George) had an ancient Bachmann 4-4-0 he sold me for the parts I needed, so I'm no longer stalled.

Four 68" drivers mounted, quartered, Bachmann rods put on, and turned with old motor in old tender for a test.   No binding, but I'm concerned how cocentric they are and if this is going to cause visible wobble.   We'll see.

The 14' 8" bolster-to-bolster distance is just a foot shorter than the frame bolster-to-bolster on a Kato caboose frame, so I cut one of those up, shortened it, spliced it, and reassembled it with JB Weld.  I've never found a solvent cement that will touch that frame plastic.   I'll use the original trucks until testing is complete, then we'll talk about replacement sideframes.   Truck wheelbase is good along with wheel diameter.   With solid 8x8 tender pickup I may be able to get away with not having the locomotive drivers electrically hot.   We'll see.

Next steps are to fabricated the gearhead, drawbar, and driveshaft replacement and I really want to see whether or not this driver replacement is actually going to work or if I just can't get those wheels good enough.    I thought they'd be miserable to quarter as they are geared; I cut a slot in one end like Rivarossi did and the Bachmann rods fit perfectly.

Cut the resin cab off of one of the two resin Trix shells (Somebody on the forums made these...back in the Atlas days..???) and it's too big but it's a heck of a lot easier to work with a resin cab to resize it than a metal one.    The boiler is just WAY too fat, anyway.

[randgust]

OK, so this thing is finally moving under its own power, however odd and awkward it may look at the moment.

Here's the good news - I'm dead-on so far on dimensions for drivers, wheelbase, and believe it or not, distance from rear axle to first axle of tender.

The cut down Kato caboose frame is also dead-on for dimensions so far.

You may not believe it, but I did turn down the flanges on the Rivarossi 68" drivers.   Those are the Bachmann rods on there.    The gearhead motor (Kato 12V + 5.14:1 Gizmoszone gearhead) is quiet and powerful.   Now that it's connected and running, the speed range is excellent.

Now for the bad news.   I've got some issues with the front axle being a bit off for wobble.   Not terrible, but before I start really working on this thing I've got to get those four driver wheels as good as I can possibly make them and its not good enough yet.      This project reminds me of the TP56 critter; I'd rather experiment and see what actually happens than debate it to death, but that doesn't mean I've got a perfect concept to start and somebody that chimes in may have some great suggestions.   Happily, all the problems are the alignment of the remounted wheels on the Bachmann axles - other than that, the whole tender drive thing work really, really well through that driveshaft - very smooth.   So now I get to pull it apart and start working on the drivers with a micrometer to see how good I can get this.

[Ed Kapuscinski]

I love watching such insanity come to life.

[Lemosteam]

@randgust, looks great so far. 

Some questions: 

Do you have more driver wheels?

Are the centers of the drivers plastic or metal?

What tools do you have to create/enlarge the holes in the drivers?

Did you press fit or try a line to line slip fit?

Did you have to modify the axle diameters at the ends at all?

[randgust]

I turned the Bachmann axles down to match the diameter of the Rivarossi ones  and put on a shoulder.   I did not redrill or change the Rivarossi wheels that have plastic centers.  The challenge was to press the wheels back on both squarely and in quarter, it's good, but not good enough, so I've got to do more work on that. 

I shouldered up the Bachmann axles in a dremel and worked slowly on them with a diamond file (axles appear to be steel).   Checked constantly with a micrometer.  Put them back on with ACC although I got better as I went for press fit.

I also have enough Bachmann axles and Rivarossi drivers to do the whole thing over if I'd have to, but so far that seems extreme.   

Right now it's just enough of a wobble to irritate me.

I wasn't sure how well the driveshaft idea would work (NWSL universal and shaft into the Bachmann shaft end), but even at full slip it's steady and there's no indication of issues when it hits curves.

I'll carve off all of the old 4-4-0 boiler that doesn't hold the worm and the frame, but I've got to beat the wobble first.

[Lemosteam]

Perpendicuularity and runout on the axle may be the issue.. I used a drill press when I did this.  It allowed me to rest my arms on the bed and hold the file very steady without having to hold the dremel.



I have found that many diamond files are not particularly square from side to face because of the way the diamond grit is added to the parent metal.  Try a fine flat file to make the diameter and shoulder simultaneously.  That shaft is likely soft metal.