Best Of Spokane, Portland and Seattle (SP&S) 0-6-0 Project

[Cajonpassfan]

For some reason I cannot open any of the photos on this thread any more, which is a shame because they are amazing. What a thread, wow! Hopefully that's just temporary...

Max, as to the idler question, a single idler should be all that's needed; I believe the worm diameter will actually be much larger than the schematic drawing shows and the distance to span thus less? Fewer gears = less friction...right?

Oh, and personally, I find the horizontal motor mount just esthetically so much more pleasing

Anyway, following this with awe.
Otto

[mmagliaro]

The pics are back.  Photobucket was dead for hours today.  That's why the pictures weren't showing up.

I really appreciate all the inventive (crazy?) ideas you guys suggested for hiding the gap and mounting the motor.
Pete, I did  actually consider doing this with a tender drive.  And of course, with 33" tender wheels, we
get that much more speed reduction, besides the other benefits.  However, the tender on this engine is
a very small slope back type, and I'd have to go with a really small motor to make it work.  I would rather tough it
out with the boiler motor and keep my 4:1 Faulhaber.

What I really was intending to do was simply cut a piece of matching round tube and put it under the motor
(the cradle idea that narrowminded suggested).   That is, in fact, how Vanderbilt tenders are made.  The chassis
is rounded up on the sides to meet the shell that comes down.  If it's done carefully, the seam isn't noticeable.  Heck,
that's how I did the Vandy tender on my 4-6-2 and I was able to machine the slot out of that brass tender body
and make it mate up perfectly with that Bachmann tender chassis. 
In this case, I'll have a a boiler with a cut-out, and I can use that opening as a pattern to scribe lines on another piece
of tubing, so I can make an exact matching "puzzle piece" (I hope!) to sit under the motor.  It can screw to the frame,
and can even be the motor mount.

Back to idlers....
I finished doing a lot of measuring, scaling, and analyzing from the prototype drawings and my gears.  I got the Kato
truck in the mail today.  The idlers are very small and unfortunately therefore won't be of any use.

It works out that I need a 32 or 33T 0.2 mod idler gear.  Whaddy know?  I just happen to have one of those.
So I will forge ahead with that.

1. Make some brass walls with bearings in them to be the idler carrier, and get that
    thing positioned right so the idler and drivers all turn smoothly. 
2. Make front boiler cradle.  It will be plastic, so a brass boiler can sit on it, be screwed into it, and be isolated
    from the brass frame.
3. Once the basic boiler is cut out, mounted, and looks right compared to drawing and photos,
    make the motor mount with that matching curved underbelly and see if I can get the gears to mesh and
    make the darn thing run. 

It will be time-consuming work (what else is new?)  But I think it allows for a lot of adjustment and trial-and-error
as I go, and that's crucial on a project like this.  The motor can side anywhere inside the boiler, really.  If I'm a little off
on the idler gear height, I can always shim and fix up or down a little and get it right.

[Chris333]

Well a 0816 +4:1 will fit in the tender, but yeah I have it pushed pretty far forward:
https://picasaweb.google.com/ErieChris333/ErieRailroadB5060NScale#5193062949740831858

Either way I think you'll be OK.

As for the idler. Sliding it back and forth around the axle gear would give you adjustability to get the motor up where you want it. They don't have to be in a vertical line. A bigger gear moved forward or back will give you more room to play.

[mmagliaro]

Well a 0816 +4:1 will fit in the tender, but yeah I have it pushed pretty far forward:
https://picasaweb.google.com/ErieChris333/ErieRailroadB5060NScale#5193062949740831858

Either way I think you'll be OK.

As for the idler. Sliding it back and forth around the axle gear would give you adjustability to get the motor up where you want it. They don't have to be in a vertical line. A bigger gear moved forward or back will give you more room to play.

Well, yes, but I don't want a drive shaft up to the engine.  If I were going to make it tender drive, I would want
to gear it to the tender trucks.  And it won't fit that way.

As for the sliding it back and forth.... YES YES YES.   And in fact, I'm glad you said that, because the gears should absolutely
NOT be in a straight line.  That's one of the problems with the Bachmann Berk.  In-line gears can be made to work, but it
is very hard to get things so perfect that they don't exert clumsy pushing forces through the string of gears.  After all,
I'm just going to eyeball this with a gear spinning around a shaft.  It's not like it's going to be some ultra-perfect
ball-bearing drive.     Much better to offset the idler a little.  That gives unpleasant upward forces "somewhere to go".
Anything that pushes up on that driver will cause the idler to deflect out a little, and that cushions any forces
exerted by any slight out-of-round, or from the drivers pushing up/down a little over the track, and so on.
Thinking you can make a machine "perfect" is a fool's game.  Much better to make it as good as you can, but design
the driveline so that it can absorb some error and still work right.

[narrowminded]

For placing that idler gear shaft location you could make a simple fixture that confirms the gear spacing fit and then holds those parts solidly in that placement while you solder, pin, or otherwise afix the idler shaft guide to the frame.  A simple set of drilled (reamed) holes of the correct diameter and spacing for the axle and idler shafts, done accurately with your mill in a piece of material that's oversized enough to be clamped to the frame comfortably outside your immediate work area, could be slid through those parts from outside the frame, all fits confirmed, and then finally fix it with that set of fixture pins and plate holding the alignment.  And if it would be more convenient to have the fixture inside the frame, now knowing the proven dimensions, a block of material that fits within the frame rails could be drilled to your good set of spacing numbers and hung in there with axle and idler shafts slid through the block and holding the alignment.  You might hold off final attachment until after you get your motor mount worked out so you can swing it up or down to get that fit too before to fix them final.  Those gear pitch line and shaft  C/L calculation numbers are actually good if the gears are proper so it shouldn't take much to work it out and knock a holder together.  Just another thought that I hope is somehow helpful.

[mmagliaro]

For placing that idler gear shaft location you could make a simple fixture that confirms the gear spacing fit and then holds those parts solidly in that placement while you solder, pin, or otherwise afix the idler shaft guide to the frame.  A simple set of drilled (reamed) holes of the correct diameter and spacing for the axle and idler shafts, done accurately with your mill in a piece of material that's oversized enough to be clamped to the frame comfortably outside your immediate work area, could be slid through those parts from outside the frame, all fits confirmed, and then finally fix it with that set of fixture pins and plate holding the alignment.  And if it would be more convenient to have the fixture inside the frame, now knowing the proven dimensions, a block of material that fits within the frame rails could be drilled to your good set of spacing numbers and hung in there with axle and idler shafts slid through the block and holding the alignment.  You might hold off final attachment until after you get your motor mount worked out so you can swing it up or down to get that fit too before to fix them final.  Those gear pitch line and shaft  C/L calculation numbers are actually good if the gears are proper so it shouldn't take much to work it out and knock a holder together.  Just another thought that I hope is somehow helpful.

This is where I'm headed (about what you are describing).  A milled-out brass box that will sit inside, between the frames,
with the shaft through it and the gear in it.  I can drill one hole all the way through, so I can insert the shaft
from that end, and then rig up some sort of pin or wire to hold it so it won't slide out while the gear is spinning.

I will spot it into the frame to make sure it is close and can allow for moving it back and forth a little for fine adjustment.
Once I get the motor mounted, like you pointed out, I can slide the gear box back and forth until I get it right, and then tack it
with some ACC just to hold it so I can test it a little, and then drill clean through the frames into the box from both sides
for pins or screws.

The slightly tricky part will be making sure the whole thing doesn't short the two frame halves together.  I figure on just inserting
a thin shim of styrene on one side.  If the box is rigid enough (and I'll make sure it is), I should be able to just
pin and solder it on one side.  The other side can have a small nylon screw, but that might not even be necessary.

[chicken45]

Wow!

[Sokramiketes]

Will it fit in the tender, driving the front truck, if you don't worry about letting the truck pivot?

[mmagliaro]

Will it fit in the tender, driving the front truck, if you don't worry about letting the truck pivot?

The motor itself would just barely fit, but then there has to be some room for the shaft and worm, so let's allow 7mm or so
for that (and remember, there's a raised nipple at both ends of the motor that is about 3mm long, so
we have 16mm motor + 7mm gearhead + 7mm worm/nipple + 3mm nipple on the rear = 33mm.
I have overlayed it on a photo of the brass HO tender for this engine, and I can see that this would place my worm, at best,
over the front axle of the front truck.  I suppose  could rig something up with idlers so it
could drive just that axle, and through idlers drive the other axle, but it would all be so close that I really don't want to go that
route.  Smaller motor?  No gearhead (and do reduction through a double gear)?  Yes, there are always possibilities.
But the engine boiler on this thing is huge (relatively speaking, for an 0-6-0) and I have more room in every dimension
than I need for the motor, so that's why I have settled on putting it in the engine.

[mmagliaro]

And now we do the idler gear and the position of the motor. 

As you look at where the motor has to go, bear in mind that
I am very open to suggestions for how to mount the motor so that there is open air between the bottom of the boiler and
the frame.  At present, I think that a boiler tube with a slim slot cut along its belly could then be slid onto the engine from the front, rather than lower it down from above.  The motor might be able to stand on two posts that sit right above drivers
2 and 3.  There are leaf springs above those drivers that would pretty well block the view of a support post for the boiler and
motor.

Anyway, onto this segment's work... the idler.

[amato1969]

Wow, crazy good stuff!   

  Frank

[Cajonpassfan]

An amazing 0- -0. Max, you've taken this one to a whole another level. Great progress!
Otto K.

[narrowminded]

It's coming along!  Nice!

[badlandnp]

Max, that is some awe inspiring micro engineering. Inspiring! It is good to see that the eyeballing works as well as the micrometer does!

[glakedylan]

Max...such a rewarding thread to keep following
your work is so interesting and skillful
thanks for sharing.
sincerely
Gary