Work begins

In case you're curious, you can see an exploded parts diagram of the AHM version of this same engine at http://www.hoseeker.net/AHMRivarossiassembly/AHM060sidetankpg2.jpg.  The only difference is the style of side tank.

Another good photo of what I'm going for comes from a 1943 Porter catalog:

The main difference between the photo and what I'm going for is that my model will have inside Stephenson valve gear.

I paid about $11 for the model on ebay, knowing that it would be little more than a running chassis.  What I received was even worse that I expected, having no bottom plate and various cracks in the frame.  Still, it seemed like a repairable model, the quality of the parts that I actually wanted is decent, so I figure I can do something with this.

I started by removing everything that didn't look like a Porter 2-6-0, including that rather large motor.

Not much left, is there?

With this much of the engine to build, where to start is far from obvious.  I decided to start with the running boards, and then work up from there.  I found a brass tube that would just accept the smaller motor I have on hand, and started figuring out where to put the various parts.  As it turns out, there is a step in the frame which is at about the right height for a running board, so that makes a good level reference surface.  I cut a combination running board and cab floor out of .032" brass sheet, since an engine this small needs all the weight it can get.

Here it is, along with the new motor:

The bar soldered to the bottom both locates the piece securely and supports the rear of the motor.  At this point, things are just stacked up loosely to see how they fit together.

There should be enough room for a Digitrax DN135 in front of the motor.  I still need to figure out exactly where and how to mount the boiler.  The motor will probably be simply taped or glued into place, but that is also to be determined.

Here are the parts I have so far, more or less laid out as they belong in the finished locomotive.  The tender tank will need to be shortened or a new one made, but that's a project for another day.

Bottom Plate

Ken,

I rebuilt a old Tyco 4-6-0 once. It was on the light side, so I replaced the bottom plate with a piece of sheet lead. it helped a lot with the engine's pulling power. That engine had the poorest excuse for a motor, oh wait i forgot about the pancake motors in the old Bachmann 2-8-0. The hotter they got the slower they went.

Anyway just a suggestion, since there is little room for weight. Just don't tell the EPA.

Regards,

John

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If there are no stupid questions, then what kind of questions do stupid people ask? Do they get smart just in time to ask questions?  Scott Adams

Thanks!

Thanks, John.  I had thought about styrene (easy) or brass/steel (harder, but heavier), but not lead.  I like that idea.  I have a bunch of lead sitting around, and I'm thinking of trying to cast a custom weight to fill as much of the boiler as possible.  Now that you mention it, a lead bottom plate makes a lot of sense.  I think I'll try that.

This promises

This promises to be great!  I like your choice, Ken: it will be a great challenge.  I would have gone for a chubbier body based on the weight, but obviously you are discarding that...  I am curious to see what you end up with.

To secure the motor get some spring wire and bend it to the shape of the motor as it sits; engage the bent ends below the floor.  If you bend the wire exactly right you should end up with two "u straps" that want to spread open but are restrained by the brass frame, and keep the motor snug.  The same can be made with a single, wide, spring steel strap.

Motor mounting

Interesting idea.  My original plan had been to solder the boiler to the running boards, but the more I think about it, it would be better to make them separate.  That way, I can mount the motor, decoder, etc. on the frame, and then just set the boiler down over them.  The way I made the running boards, with the shelf for the motor to sit on, the motor ends up being captive if I solder the boiler in place.  I really like your suggestion of a spring clip, and I think I have the perfect material and location for it.  I'll see what I can come up with.

As far as the weight, I have not yet built the boiler, so I could make it as large as I like, but I'm afraid it would be out of proportion and ruin the lines of the engine.  I'm confident that I can hide enough weight in there to make it handle 2-3 cars reliably, and that's about all that the prototype would have been asked to move.  If an N scale locomotive can be made to work well, then I ought to be able to pull it off in HO.  That's why I'm working in brass this time, though.  I need all the extra weight I can get.

Motors

Ken,

If you find that a more powerful motor is needed, I have used a couple of motors from Jameco. The are in the $3.00 to $10.00 range. The company has data sheets on line that give current, voltage, RPM, Torque, and dimensions. They have several that are in the 12V range and less than an inch in diameter. they only sell single shaft motors, but these are good for most steam engines.

I usually run the motors for an hour in both directions and check for defects, I make it a point to buy at least 2, so I have a spare. The motors I have used are cheaper than a brush set for my older motors.  The 232144 and the 231732 parts look like good candidates. The motor stock changes, so you may not find the same motor in 6 months. The bad news, I have purchased a motor from this vender that was not suitable, but the good news is most of their motors were good performers.

http://www.jameco.com

Regards,

John

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One of my favorite philosophical tenets is that people will agree with you only if they already agree with you. You do not change people's minds. Frank Zappa

frustration

First of all, thanks for the suggestion on the motor mounting clip.  I made one and installed it, and it looks like it'll work fine.  I need to tweak it a little, but I expected that.

I made a boiler and smokebox this afternoon, and (after realizing that the smokebox was drooping and re-soldering it) I discovered that the boiler is going to ride rather high.  Maybe too high - I'll have to clean things up a littler and see how it will look in its final place.  I may end up making a larger boiler, just so that it can appear to sit lower.  The top height is dictated by the motor, but a larger tube can have its center lower and still work.  I'll have to balance small boiler vs. low boiler.

No pics yet, I have to get ready for work.  We'll see how it looks when I get home in a few days.

Camelback?  Good for hiding

Camelback?  Good for hiding the high motor, but bad for most prototypes!

Did Porter make a camelback?

Ugh..  What a funny concept, a Porter camelback industrial 2-6-0

I need to sit down and sketch the engine, to see if this is going to work.  If not, I have two realistic options as far as I can tell.  One is to increase the boiler diameter, as mentioned, though I really don't think that will look right either.  The other is to go back to a tank engine, since the tank can hide a much larger motor, or allow the boiler to sit much lower.  A quick measurement shows that the top of the boiler sits about 10'6" above the rails, so there's plenty of room for all sorts of tanks up there.  I'm guessing that a loco like this would have been about 13'-14' tall over the cab roof and stack.

What I am really hoping will happen is that when I sketch the model in CAD, I'll decide that it's not as out of proportion as I initially thought.  It would be nice not to lose the work I've already put into the model.  Plus, I was just starting to get used to the idea of having a tiny 2-6-0 putting around the layout.  I may even decide that I like the idea so much that I scrap the model and use the motor and drivers to make one from scratch.

Stay tuned...

Major modification

Well, Plan A didn't work out so well.  Since I don't want to give up on this project, I needed a Plan B.  As I mentioned above, I had some ideas, but nothing jumped out at me.  I was going to make new frames out of brass and scratch build a loco using the drivers and rods, but I decided to hack up the Bachmann frame, figuring that I have nothing to lose.  There's not much left, but at least it keeps the axles at the right spacing.

I am ditching the internal gears which powered each axle, and driving the rear axle directly off the motor.  It'll be fast, but hopefully I can control it with decoder programming.  As it turns out, the frame already had a nice flat spot at the perfect height to set the motor, and the motor I'm using is exactly the same width as the frame.  Sometimes things just line up nicely.

So, without further ado, here's the newly modified frame, along with the likely candidate for a boiler, and a shot of just how much I had to remove.  Compare it to some of the earlier photos!

I am hoping to be able to salvage the original electrical contacts and the plastic side pieces which held them in place, especially since those pieces have the crosshead guides cast into them, and it would be nice to retain those.  I'll have to figure out how to make and mount a new front frame section, but I don't think that will be too bad.  Also, it turns out that the axles snap into the frame so tightly that I might not have to bother with a bottom plate at all.  We shall see.

How about this fatboy?

Could you build this?  The wheels are probably smaller here in the photo, but I bet you could come close.

Den

OK, now...

...it's becoming a really interesting project!

Only now?

What are you saying?  Was it boring before?   It is turning into more of a project than I had expected, but in some ways this will be easier, because I won't have to work around what Bachmann built.

Time for a little confession, too.  I'm working in brass because this engine really needs the weight.  I didn't build the last one out of brass because I didn't think I had the skills.  I taught myself a lesson and am taking my own advice, that I can do anything if I want to try it.

brass

My first attempt at building a loco from scratch was brass.  It was an American 4-4-0 and I still have the (solder-splattered) domes, lamp and lamp bracket, check valves, whistle and drivers,,, Not sure of what I did with the scratch-built double diameter boiler... it disappeared years ago. I remember I had even done the bands on it...  The cab was wood, and also has gone missing.  Never got to the frame, or the tender.

I think this might actually work

This morning's progress:

I'm still on the fence about the gears. With them in place, the wheels do not turn smoothly (even without the side rods). It feels like the gears are not meshing properly. If I can make it run well without them, I might just leave them out. On the other hand, if I can find the gear problem and solve it, I like the more robust gear drive. Not that that little motor is all that robust..

I trimmed the side pieces which hold the wipers in place, as well as having the crosshead guides and brake detail. They were originally held in place by two screws (one of which was in the portion I had to remove), but by leaving the bosses cast onto the frame sides there is enough registration to make them secure with a single screw. I have not yet modified the wipers, but I foresee little difficulty there.

One nice thing about moving the motor is that it makes it practical to attach the running boards to the boiler. This morning I modified the running boards to suit the new motor mounting, and soldered the boiler in place. It feels much stronger now, and I like the way everything fits together neatly.

And, in case there was any doubt how small this thing is, here it is shown next to a Spectrum low boiler 4-6-0, one of my smaller locomotives.

A little more progress

No picture, because other than the rods there's not much new to show.  I decided to ditch the gears and use the rods to power the drivers.  The first step was to glue the gears and wheels to the axles, since both could spin all too freely.  It's an interesting design, but apt to get loose and let one or both drivers turn on the axles.  I fixed that!

I tried an experiment with quartering, and it worked out well.  Maybe I was just lucky, but I think it was actually a decent idea.  Using an ultra-fine Sharpie, I marked the driver tread (and then the flange and wheel back) at the crank pin, and at a spoke exactly 90 degrees away from the crank pin.  I marked all 6 drivers exactly the same.  When I assembled the axles, I carefully lined up the marks by eye.  To make sure I was looking straight on, I would squint and align the closer driver exactly in front of the other, and see if the black marks lined up.  The second set of marks gave a good double check of the alignment.  With a mix of confidence and hope, I glued everything up without any way of making sure I was right.  When I assembled the rods, everything tunrs smoothly with no binding, so I got it right on the first try!

I lost one of the little pressed in crank pins, so I decided to replace them all with 00-90 hex head screws.  They will just thread into the crank pin holes, so I didn't bother tapping the holes in the drivers.  I did have to thin the heads to clear the crosshead guides, but that was simple enough.

I also soldered the two-piece wipers together and trimmed them to fit the smaller frame.  It's starting to come together.  Now I just have to figure out how to mount the motor.  I'm thinking of soldering something to the steel case, since I took it apart to clean some metal filing out of the magnets.  The joys of designing on the fly...

Magnets & heat

Careful soldering there. Magnets loose strength when heated, but may not be enough from a soldering iron to hurt them.

Bernd

Motor mounting

Bernd,

Note that I mentioned taking the motor apart.  I wouldn't heat the magnets, but at the moment I have the steel case separate from the rest of the motor.  I'm trying to come up with a good clean way of mounting the motor, and being able to solder to it might make things easier.  If not that, maybe I'll be able to drill and tap the case for screws.

Assumption

I made the assumption that you had put it back together again after cleaning it.

Bernd

Good assumption, but..

Well, I was going to, but I ran out of time, so it's still in pieces.  Sometimes you make lemonade..

I tried an experiment with

noted, thanks.

That's an old trick

Modelers have been using a variation on that for years.  Usually they scribed a small line from the center of the axle out onto the wheel hub using a sharp knife or similar.  When they reassembled the wheel, they just lined up the scribe marks.

Makes sense

If I'd had the wheels properly quartered to begin with, I probably would have done that.  However, the process of removing the wheels from the frame caused them to twist on the axles (yeah, they were that loose), so I had to find a way of establishing consistent quartering from scratch.  I've never owned a quartering tool (kind of odd, given the number of steam models I have taken apart), so I'm always looking for creative and effective ways of getting the job done.

Fun with props

One of the advantages of having your own locomotive scrap yard is that there are plenty of parts to play with.  To make sure things are going in the right direction, this morning I propped up some spare cylinders, domes, a cab, and a pilot.  I tried to get a stack to sit there, but without a base it just kept falling off.  Same with the slightly undersized boiler front casting I have on hand.

The domes are the wrong style (and there should be a second sand dome), the cylinders are too large, the cab is too wide, and of course the tender is too long, but all in all I think it's coming together nicely.  I may end up using that pilot beam, if I don't need it for the engine came off of.  The tender I'll shorten, or replace.  The cab, domes, and cylinders I'll scratch build.  I'm wavering between using styrene for ease, and brass for weight.  Decisions, decisions!