ATSF 3460 Blue Goose Build

[Cajonpassfan]

Well Drasko,
it depends on what you mean by better. Easier, yes, more practical, certainly. It's just that I have this thing about steam locomotives and their hierarchy and in my head, it all starts with the relative size of the driving wheels. There were tons of fast Pacifics, Hudsons, and Northerns, but in my book, in North America, there were only three modern big wheeled passenger engines in a class all of their own, with their huge 84" drivers: C&NW E-4's,  Milwaukee F-7's, and Santa Fe 3460's, all weighing in at 412 tons plus for the engine alone. I'm thinking a model needs to FEATURE the driver size. That's why I'm trying to figure out how to do this so that when I park it next to a Northern, I can see the difference.....your mileage, or driver size, may vary

Robert, thank you for your very kind offer. What I need is actually not that complicated, just a 1.8 mm (or .071") solid Delrin  or equivalent rod. It doesn't need any holes and I can cut it to length easily enough. (The three axles are .447" or 11.35 mm long each). The collars (6) should have an o.d. of 2.96mm, i.d. to fit snugly over the axle, and a thickness of 1.5 mm. Again, I can fabricate these from two layers of brass tubing, but a lathe could make a quick work of that.

Thanks for your comments guys!
Otto K.

[draskouasshat]

otto, I  know this.  I'm telling you to put said 84" fvm drivers  in said Kato gs4 mechanism.  I'm trying to save you some work or give you another option. granted I'm in Wisconsin for work and limited to what nscale projects I could fit in my bag for an airplane ride so I don't have any of my gs4 or cc Hudsons in front of me but I would think it would be easier to fit 84"  drivers in a frame that had 80" drivers like the Kato instead of in a frame with what are undersized 74" drivers.  granted you well still have to file the bearing boxes to slide the drivers for correct space but I would figure it would be a helluva less  than what you're having to do now!
I would much rather fit an 84"driver where an 80"used to be instead of an undersized 74" and still achieve the correct wheelbase. take it for what it's worth lol.  Good luck
adam

[robert3985]

...Robert, thank you for your very kind offer. What I need is actually not that complicated, just a 1.8 mm (or .071") solid Delrin  or equivalent rod. It doesn't need any holes and I can cut it to length easily enough. (The three axles are .447" or 11.35 mm long each). The collars (6) should have an o.d. of 2.96mm, i.d. to fit snugly over the axle, and a thickness of 1.5 mm. Again, I can fabricate these from two layers of brass tubing, but a lathe could make a quick work of that.

Thanks for your comments guys!
Otto K.

Otto,

I can do this in one piece.  Is there a need for brass collars, or would a solid Delrin part work okay with the collars being integral?  Or, are you using the collars as an adapter to fit the old drivers' axles into halfway, and the other half of the collar fitting "snugly" over the Delrin axle?

Please 'splain 

Here's a preliminary drawing of your part as a one-piece Delrin part with integral collars on either end:


Remember, I can make this part out of Delrin, Nylon, Aluminum, Brass or Steel...which are the materials I've got on hand.  Brass and Aluminum are very easy to work with, and would be more durable than Delrin if the axle doesn't need to be made from a non-conducting material.

I'm not certain what you need the collars for.  If they're just spacers, then the integral design works okay as long as you don't have to insert the .071" shaft into bearing blocks.  If they are both spacers and adapters to fit between the driver axles and the Delrin axles, I can think of at least a couple of stronger ways of doing this.

I'm probably thinking too much and trying to visualize how you're going to attach the drivers to these.  If we can incorporate more "meat" into the design and use a sturdier material in place of plastic at critical mounting and bearing points...that'd be much better.

[nscaleSPF2]

Not sure if this will work or not, but here is an off-the-wall idea.  How about a wooden axle?  I measured some round toothpicks; they seemed to be about .065 dia.  They could be sized to fit inside metal sleeves for the wheels and/or axle bearings.  The wood could be sized by drilling a hole thru a piece of steel of the desired dia, and then pushing the wood thru the hole.  I believe that this is how wooden dowels are made.  The wood would probably be stiffer than plastic, and could be sealed to prevent warping due to moisture and oil absorption.

For what it's worth.

Jim

[Cajonpassfan]

otto, I  know this.  I'm telling you to put said 84" fvm drivers  in said Kato gs4 mechanism.  I'm trying to save you some work or give you another option. granted I'm in Wisconsin for work and limited to what nscale projects I could fit in my bag for an airplane ride so I don't have any of my gs4 or cc Hudsons in front of me but I would think it would be easier to fit 84"  drivers in a frame that had 80" drivers like the Kato instead of in a frame with what are undersized 74" drivers.  granted you well still have to file the bearing boxes to slide the drivers for correct space but I would figure it would be a helluva less  than what you're having to do now!
I would much rather fit an 84"driver where an 80"used to be instead of an undersized 74" and still achieve the correct wheelbase. take it for what it's worth lol.  Good luck
adam

Well, thanks Drasko, apparently I missed your point. That may indeed work. For what it's worth, I'm too far into this to change (iron) horses now. I don't own a Kato GS4 to check, but out of curiosity, what is the actual model driver diameter? Is it 80"? And driver spacing? Also, isn't the driver spacing unequal, at least on the prototype?
Maybe I need to acquire a GS4, for other projects...
Otto

[Cajonpassfan]

Bob, wow, you're awesome, thank you!
I'm attaching a pic to 'splain myself....as you can see, the CC drivers have an integral collar on the back that fit into brass bushings which slide into slots in CC frame. It's all in the photo.
The FV drivers are an open casting and just have a brass tube center which I already reamed out as much as I dare to accept the axle. I used a #50 bit. The axle will be press fit into the reamed out opening and does need to be non conductive. A thin brass washer will slide up against the driver, followed by the brass collar followed by the CC gear casting, and then the other side gets installed, in reverse order, and then the assembly gets quartered. In theory anyway...
Otto K.

PS: the collar needs to be conductive...it's how the power gets transmitted to the frame. Brass, or steel, or?

[Cajonpassfan]

Not sure if this will work or not, but here is an off-the-wall idea.  How about a wooden axle?  I measured some round toothpicks; they seemed to be about .065 dia.  They could be sized to fit inside metal sleeves for the wheels and/or axle bearings.  The wood could be sized by drilling a hole thru a piece of steel of the desired dia, and then pushing the wood thru the hole.  I believe that this is how wooden dowels are made.  The wood would probably be stiffer than plastic, and could be sealed to prevent warping due to moisture and oil absorption.

For what it's worth.

Jim

Jim, thank you for the suggestion.
Frankly I didn't consider wood.... It's not a material I associate with steam locomotives, except for wood burners...
Seriously, the cross section of a 1.8mm dowel is tiny and I'd guess probably not strong or stable enough for this application...? And even if it were, something about a wooden locomotive axle rubs me the wrong way... maybe I need to think more out of the box...
Regards, Otto K.

[draskouasshat]

otto  I'm in Wisconsin for work so I can't take any measurements. I do see the front driver is kicked forward but I can't take any measurements without a model in front of me.

[Lemosteam]

I was in an aircraft hobby shop the other day and they had various diameters of carbon fiber rod for servo linkage or wing spars or something.  That should be well strong enough...

[Cajonpassfan]

John, thanks,
I looked at carbon fiber also, and while it is extremely strong, I need something totally nonconductive and I believe carbon fiber does conduct electricity, albeit badly. The two half frames would short...
Otto K.

[Cajonpassfan]

otto  I'm in Wisconsin for work so I can't take any measurements. I do see the front driver is kicked forward but I can't take any measurements without a model in front of me.

Uhh, sorry, enjoy the weather...

[robert3985]

Bob, wow, you're awesome, thank you!
I'm attaching a pic to 'splain myself....as you can see, the CC drivers have an integral collar on the back that fit into brass bushings which slide into slots in CC frame. It's all in the photo.
The FV drivers are an open casting and just have a brass tube center which I already reamed out as much as I dare to accept the axle. I used a #50 bit. The axle will be press fit into the reamed out opening and does need to be non conductive. A thin brass washer will slide up against the driver, followed by the brass collar followed by the CC gear casting, and then the other side gets installed, in reverse order, and then the assembly gets quartered. In theory anyway...
Otto K.

PS: the collar needs to be conductive...it's how the power gets transmitted to the frame. Brass, or steel, or?

Otto,

Okay, now I get it.  I'll machine 5 black Delrin axles that are exactly .071" dia., by exactly .471" long (two extra axles for whatever reason), and 10 collars that are a light friction fit on the axles, but which can be slid on them without marring the surface finish...they'll be exactly .059" thick with an O.D. of exactly .117".  The center hole will probably be as close to exactly .071" as I can make it.  Everything will have lightly dressed edges (no burrs) and the axles will have a shiny, smooth surface (not polished, but very fine).

I should be able to do these on Monday, so PM me with your mailing address and I'll get 'em out to you on Tuesday.

[Cajonpassfan]

Otto,

Okay, now I get it.  I'll machine 5 black Delrin axles that are exactly .071" dia., by exactly .471" long (two extra axles for whatever reason), and 10 collars that are a light friction fit on the axles, but which can be slid on them without marring the surface finish...they'll be exactly .059" thick with an O.D. of exactly .117".  The center hole will probably be as close to exactly .071" as I can make it.  Everything will have lightly dressed edges (no burrs) and the axles will have a shiny, smooth surface (not polished, but very fine).

I should be able to do these on Monday, so PM me with your mailing address and I'll get 'em out to you on Tuesday.

Wow. Thank you.
The dimensions are correct except for the axle length: it should be .447", per your original drawing.
PM follows.
Otto K.

[peteski]

Is it desirable for the metal collars to be light friction fit on the axles?  Won't the drivers go out of quarter easily?  Oh, the collars will not sit on the ends of the axles but behind the wheel?  The tight fit will be between the 0.071" axle and the center hole of the FVM driver?

Also, how will the metal collars get electrically connected to the metal tire on the FVM drivers? Thin large diameter washer?

I thnk that I might have figured it out - in bold

[mmagliaro]

Carbon fiber rod does indeed conduct, and quite well.  It would form a dead short.  I've wanted to use those hobby shop carbon fiber rods for exactly the same purpose in the past, but it's a no-go.