Best Of SP&S 4-4-2 Atlantic project

[mmagliaro]

EDIT... (see end)

Yes (definitely NOT that I am genius,  ) but will you have enough length in the slide bars to do that?  I ask because the main rod will pull the slide farther back or will you make new mains?  I do think you may want to lengthen the boiler a bit when you do that because the overhang from the smokebox front to the cylinders will be very small.  I may have something that can help you and I will contact you via PM.  Something from a certain, very special PRR boiler designer...

Actually, yes!  The slide bars extend back too far over the front driver anyway, so pulling them forward will
correct that as well.  There is extra at the rear of them, so the valve slider won't "pull off the back" of them.
BUT....  I hear you on the overhang of the boiler.  And not only that, but although the steam pipes aren't there,
the stack is supposed to line up over the cylinders too, so that would have to move forward and there really
isn't room.  It might be best to leave it the way it is.

I'll look for your PM.

Hmmmmm. wait just a minute here.  This thing was originally cast from a Trix B6.  So maybe I can slice the front 1/8" off a b6
metal shell. and epoxy it right to the front of this engine.  Shave off the smokebox band (replace that with a thin band
of styrene, like I will do with the other boiler bands), get rid of the existing headlight, handrail, etc.  Basically just splice on
a new "nose".

[mmagliaro]

Update.
The pics pretty much have all the annotations in them to explain what's done so far.

I rigged up two phosphor bronze springy contacts so that the boiler can be completely removed
with no wires going to the headlight.   I had to really bend, cut, epoxy, and remount the valve
gear hangers to get them at the proper height and orientation.  I was trying to avoid that,
but it was the only way to get them right, and now I think the walkways are riding at the right
height just at the top of the drivers, and there is a gap below the walkways, to the
the hanger, so the cooling lines can fit in there.

I also did a lot of general cleanup and smoothing on the boiler, walkways, and cab.








I know I'm slow.  But these things take a long time (and I love every minute of it).

[Lemosteam]

Max do you do that headlight thing with the fiber optics in the headlight or before you put the optics in the headlight casting?

The model looks really great!

[wazzou]

Fantastic.  It's amazing work.  I'm always in awe of people that can tinker with a small model steam engine and get it to look good/better and run well also.

[mmagliaro]

Max do you do that headlight thing with the fiber optics in the headlight or before you put the optics in the headlight casting?

The model looks really great!

Thanks, John!  Even though the boiler is a little short compared to the prototype, I think the overall proportions look good. 
The more I pick at those rods, the better they look.  I am still going to be picking, straightening and smoothing them.  Just like
the boiler, it's a continuous process.

And thank you, Bryan! I think these small steam locos are much harder to do than the big ones.  Everything is so small and compact.

Your question made me realize that lighting these steam headlights that sit on top of boilers, with a fiber optic tube,
is a whole little project to itself.  I wish I had taken a series of photos.   But here goes...

1. Drill a hole straight into the front of the casting, almost all the way to the back.

2. Drill diagonal hole up from the lower rear corner to meet the first hole.  Drill it up through the bottom, however,
at a 45 degree angle, NOT through the back or the actual corner.  Remember, when the headlight casting sits
on top of the boiler, you don't want this to show.

3. Drill a 45-degree angle hole in top corner of the boiler, all the way through to where it will reach the internal LED.

4. Push the fiber optic tube through the front.  It goes straight in, and then curves down that 45 degree hole just fine.
  Push it well into the boiler, so it snakes out the bottom.

5. Use a drop of ACC to get the headlight casting to stay put in the correct spot.  This can sometimes be a pain, because
the fiber optic tube might "fight you", trying to ever so slightly nudge the headlight casting up, down, left, right, whatever.
But if you can hold it in place long enough for the ACC to set, it will stay.  Then, back it up with JB Weld, delicately applied
everywhere you can so that it won't show when it's painted.

6. After the epoxy is hard, with about an inch of tubing sticking out the front, I hold a soldering iron
under the tube about 1/4" back from the front tip, and gently bend that 1/4" down so it makes about a 45 degree "dogleg" at
the end of the tube.  This is so that when it's
shoved in all the way, that last little bit will be horizontal through the casting.  If you don't do this, the tubing will be kind
of pointing up at a 45 degree angle inside the headlight casting and it doesn't shine straight out.

7. Now, finally, to the part you really asked about
Still with the tubing sticking out an inch or more from the front of the engine, hold the barrel of the iron as close as you can get
to the tip of the fiber optic tube without actually touching it.  if you touch it, it will stick, melt, ick.  But you can pull away, and then
hold it close, and it will still smooth out and dome up nicely.  You can't make this mistake very much, because you will melt the
tubing back past your 45 degree "dogleg" and then have to cut it off and bend a new dogleg.

I move the iron up/down left/right so the dome forms as uniformly as I can get it.

Now, you can just push it into the casting.  If you get the dome size right, it will fit nicely and fill the casting as in my photo.
If you get it too small, you can push the tube back out from underneath and heat some more.  If it's too big, cut it off and try again.

This is why you want to leave several inches of excess tubing sticking out inside the boiler. 

When you finally get it just right, you can cut off the tubing inside.  Make a SHARP flush cut (I use diagonal cutters that
I only use on soft materials, so the edges aren't all nicked up).  That's important to how much light
the tubing will pick up from the LED.

[Lemosteam]

Max, thanks for the explanation and I understand completely- the only thing you left out was the FO diameter you start with!    And a follow-up,  what happens if the FO gets scratched on the way down the 45 degree bend?  Ever try to put brass tubing in there first so there is a smooth surface inside.  Not questioning your results, just brainstorming...

[mmagliaro]

Max, thanks for the explanation and I understand completely- the only thing you left out was the FO diameter you start with!    And a follow-up,  what happens if the FO gets scratched on the way down the 45 degree bend?  Ever try to put brass tubing in there first so there is a smooth surface inside.  Not questioning your results, just brainstorming...

I use .040.  That's the biggest I can manage, and it carries a LOT of light.
I've tried .020 and the light output is a little weak. 

I don't have any .030, but that would probably be an ideal compromise for ease of installation and light output.

I don't think it matters a whit if you scratch the outside a little.  If you scratch it a LOT, it might degrade the light.
But remember, we're only talking about 1 or 2 inches of fiber optic cable at the most.  So even a darn lousy
cable can carry enough light to make a nice headlight.

What matters a LOT more is getting the LED right smack up against the end of that tube.  Even a short gap substantially
drops the light you get out the other end.

[peteski]

Max, couldn't you just mount a 0402 SMD LED right in the headlight housing (for maximum light output)?  They have a footprint of only 0.020" X 0.040".

[delamaize]

Max, couldn't you just mount a 0402 SMD LED right in the headlight housing (for maximum light output)?  They have a footprint of only 0.020" X 0.040".

THIS.^^^

That's how I did the lights on most of my projects.

[mmagliaro]

Yep.  If you want to put an SMD up in there, have at it.   I didn't realize they made them quite that small.
I have some 0603, which won't quite fit.  But 0402 ought to fit just fine.
If you can solder some magnet wire to those tiny things, that would be less work and you could run
magnet wire down a thinner hole.

Although, the hard part of this wasn't really drilling the hole and snaking the fiber optic tube in.  The hard part
was rigging up those phosphor bronze contacts so the boiler didn't have to have any wires going to the frame.
 That part has to be done whether you use fiber optic or an SMD LED.

Yeah, next time, I'll see about using an 0402.  Thanks.

[victor miranda]

I have been trying to think up a way to do the 0402 led
 in a head lamp casing for a while.
I'd like it to look good... and the pumpkin glow you get with plastic
is not my idea of good.

this leads to metal head lamp cases and the possiblility of a short.

and darned few options.

soldering the wires to the LED and encapsulating in a dot of epoxy
seem the best bet. 
The wires are very delicate points of failure with this option.
a more robust solution is desireable.

victor

[Lemosteam]

If the magnet wire's coating is still intact after soldering, shrink tube the two together , with a small, mushroomed FO stub right in front of the SMD and another larger piece of shrink tubing holding that and covering the rest of the magnet wire leads at the SMD should prevent a short in the metal headlight housing.  Feed the small shrink wrap down the hole until the "light assembly" is fit into the housing and solder it to the two tabs that are buried in epoxy and you should get your contact.  This is very similar to what I did on my B8a backup light with the tabs on top the motor,

[mmagliaro]

I have been trying to think up a way to do the 0402 led
 in a head lamp casing for a while.
I'd like it to look good... and the pumpkin glow you get with plastic
is not my idea of good.

this leads to metal head lamp cases and the possiblility of a short.

and darned few options.

soldering the wires to the LED and encapsulating in a dot of epoxy
seem the best bet. 
The wires are very delicate points of failure with this option.
a more robust solution is desireable.

victor

Victor, I'm not sure which way you mean here.  Do you not like the look of fiber optic plastic, i.e. domed over,
or do you not like the look of the SMD plastic package when it glows?

Once upon a time, MV Lenses made nice little 2-piece lens sets, a silver reflector back and a clear lens front.
You had to drill a minute hole in the center of the back of the reflector, and put your lamp or LED right behind
the back, behind the hole.  The pinpoint of light would get inside and then reflect all around inside the
lens/reflector assembly, producing a really nice look because it's almost like a real headlight.

[victor miranda]

Hi lemosteam,

I am not sure what "small, mushroomed FO stub right in front of the SMD " means.

the other thing that has my curiosity is where you get shrinkwrap
small enough to seal two magnet wires of 30-40 guage.

what I don't see is a way to protect the magnet wires from fatigue,
or a way to re-solder it, should it break.

I want easy and robust.

given how hard it is to work on 0402 LEDs,
easy is pretty much out the door.
so I think making sure one does not have to do it ...again...
is very desirable.

[DKS]

I am not sure what "small, mushroomed FO stub right in front of the SMD " means.

Take a piece of fiber optic. Heat the end to form a mushroom-shaped cone of the desired diameter. Clip it off at the base of the mushroom and position against the surface of the LED.

he other thing that has my curiosity is where you get shrinkwrap
small enough to seal two magnet wires of 30-40 guage.

Shrinkwrap comes as small as .014 OD/.007 ID, .002 wall thickness (Cobalt #P2-014-002-CLR), and is available from Small Parts, Inc. http://smallparts.com

what I don't see is a way to protect the magnet wires from fatigue,
or a way to re-solder it, should it break.

Recommend applying a small blob of epoxy to the back of the LED to encase the solder joints and the end of the shrink wrap to form a strain relief.

Actually, given the way the headlight is designed, the entire assembly (fiber optic lens, LED and wires) could be "potted" inside the headlight shell with epoxy. Then you'd have only the shrink-wrapped wires coming out the bottom, which should make things pretty simple and robust.