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

[mmagliaro]

The 2 vises look similar, but all the workings of mine are under the vise. Sometimes I stick my finger down the jaws and reach under to hold the pin while moving to the next notch. If not I might un-thread the bolt out if it and 

Neither one is ideal.  They are not really "precision" vises.  The one I really want is more like:
http://littlemachineshop.com/products/product_view.php?ProductID=2500

That one is designed to keep positive downward pressure on the movable jaw (like yours), but without any
hassles opening or closing or clamping in it.

When I want really precise work, I clamp everything down and then use a dial indicator to tweak the position of
the part.  It's really the only way, especially in a "mini mill", which is "ok", but ain't no Bridgeport or other
professional grade machine.

[glakedylan]

Max
very interesting thread
it is good to see what you are able to achieve from scratch
amazing
simply amazing
keep up the super work
thanks
Gary

[sirenwerks]

Max, your steam threads are like a David Lynch film; all creepy and scary technical and hard to follow, but with a thing of unique beauty at the very end.

[mmagliaro]

Oh no!  Hard to follow?  I guess I need to take more pictures.   

[mmagliaro]

I've reached one (of many) points in this project where I could use some opinions.

We have talked about using a larger axle gear vs idlers to get from the motor worm down to the axle.
I took actual measurements to see just how this motor is going to fit into this engine.  And it's looking to me
like idlers are really the only way to go.  Look at what I drew below and tell me what you think.

First, here's how the 8mm motor would fit inside the boiler, which will be 12mm (12.38 according to the prototype drawing,
but let's allow a little for some wall thickness).



That leads me to conclude that I'll have no trouble putting the motor inside, and the boiler opening underneath, to allow slipping over the motor, will be on the underbelly enough that it won't show.

Now, the side view:


The good news is I won't have any trouble with length and the motor will fit in there fine.  But clearly there's too long
a distance from the motor shaft down to the axle gear to do this without an idler.  The axle gear would have to be
enormous.  (And I wouldn't want it sticking out the bottom of the engine anyway).

I think I could drop the motor somewhat down into the frame, perhaps 2mm or so, but that's about it.

So... it's looking like idlers.  Am I wrong?

[peteski]

I don't see any problem using idler gears - most commercially made models have one or more idler gear between the worm and the axle gear.  Another possibility might be to angle the motor downwards to get the worm meshing with the axle gear.  Who says that the motor has to be horizontal?!    I recall seeing such arrangements in models.

[Chris333]

Gears? All I think about is how the boiler will look from the side with that cutout    Maybe if you lowered the motor down just till it was level with the bottom edge of the boiler it would still look like all one piece from the side. But yeah I see no problem with an extra gear.

Extra points if you line up the gearhead/ motor spice line with a boiler band 

[mmagliaro]

I'm not worried about the cut-out.  If you think about how all commercial plastic boiler shells look, they are pretty much
all open in the lower half, much more "cut-out" than my drawing.   They only really go all the way around underneath
up at the front near the smokebox.

How else are you going to get the shell down over a motor unless there's a cut-out?

[peteski]

How else are you going to get the shell down over a motor unless there's a cut-out?

Tender drive.       That is how Fleischmann does it. Their steam locos have not only completely closed round boiler, but also the gap between the bottom of the boiler and the frame.  Just like what you aiming for.

But on the serious note, if you really wanted to go nuts, you could fabricate a curved piece which would fill the hole in the boiler and attach that piece to the bottom of the motor.

[Chris333]

Oh I know. Guess you might be able to put the cut out part under the motor so it looks full round. But I'm sure you have a bunch of jewelry to mount on each side that will hide it. My 0-6-0 is solid so I can't talk.

I didn't see in the drawing where the tungsten goes 

[narrowminded]

If there was any benefit to it at all, the motor mount could be made from a 12mm diameter segment of solid with the motor diameter bored into it making it a cradle of sorts.  If you took that end view above and just drew a line up one side, over the motor, and back down the opposite side, that's your part profile.  There would be the cut line but just the line, not a void or abrupt profile change.  I don't know the prototype boiler to frame mount detail but maybe that could be incorporated into the motor cradle.  It could be fairly heavy, too.  That could also have the idler pin arrangement and location built in/ on to it if convenient.

[Lemosteam]

Max, you could simulate a gear tower from a diesel truck in there with some vertical plates and holes for the gears to ride in.

As far as the cutout goes, by the time all of the walkways and appliances and piping are added you won't see a thing.

Also there is no reason the motor has to be horizontal. \Can you get there tipping the front (rear?) of the motor up to get the worm closer within the ID of the boiler tubing?

[mmagliaro]

In order to angle the motor down to get the worm closer, I would have to significantly ream away
the insides of the frame halves.  The motor itself is about as wide as the frame.  I don't want to give up the frame
thickness or strength, so that is out. 
The boiler itself sits up pretty high off the frame if you study the prototype photo I posted, so the motor will have no problem
fitting inside it and clearing the drivers because it is above them.  But trying to lower it would be impossible.  Plus,
if I drop it any lower than the bottom of the boiler (which remember, does not sit down on the frame, but quite a bit
above it), then the wider part of the motor would be lower, which means it would be hanging in that open space
between the bottom of the boiler and the frame, and that might be quite hard to hide.

All the way around, just mounting the motor so it will sit at the belly of the boiler height, and using idlers to get down to
the axle is the way to go.  I am pretty sure that's the best way to do this.  And yes, my plan is to solder or screw some plates onto the frame to form the sides of a tower to carry the idlers (might need more than one).  That will also work out
because right over that rear drivers is where the firebox goes and it's a dead vertical one so the insides of it can carry
the idlers and also hide them and the worm.

And Chris, John, you are right.  There will be so much "stuff" under the walkways that any opening in that boiler
under there will never show.  The firebox will completely hide it over the rear driver, and forward of that, we have
big leaf spring assemblies and a large air tank and compressor (on the other side that isn't shown in my prototype
photo).   Modeling the leaf springs should be a hoot.  I haven't quite figured out how the heck I'm going to do that.  But
they are such a spotting feature on this engine, I have to do a special job on those.

[rhiadon]

I have zero experience in this area so my thoughts may be completely out of order here. When I read this, I wondered immediately about using a flex shaft from the motor attached to a worm gear that is at an angle to mesh with the drive gears on the wheels.

Is such an idea way wrong?

[narrowminded]

  ...Or a segment of that tube that fit the cut out with a couple of cradling plates out of .020" or so, cut to fit the tube segment I.D. and the motor O.D. might be feasible. Or lengthwise brass rounds soldered in place, right and left, that cradled the motor without exceeding the width dimension.  Not unlike what Pete said above.  Might be easier to make.  A break somewhere in the middle of those cradling wires with a thin strap soldered to the shell segment to serve as a mounting band.  Or if the proportions allowed, a notch somewhere in the middle of those cradling wires that let a band pass under them and clamp in that way.  This may get too busy or real world proportions may not make this practical but... 

And one last one with the same basic concept but using tubing in lieu of the solid round. Two small tubing segments on each side (four total) with a break in the middle, the width of a strap clamp, that would allow a thin (.005"?) strap to fit.  That strap could wrap around a music wire passed through the two tube pieces, not unlike a hinge, and would allow those straps to hinge out of the way for removal, swing back in to clamp, and that clamp might be sufficient with something like a little O ring putting tension between hooks bent in each strap end or more substantial hook soldered at each end.  Something like that might be pretty substantial while not being so difficult to make.