2-10-2 project idea

[SkipGear]

Also, the traction tire does not have a pin hole in it.  So to get perfectly quartered on would not to build a jig to drill the pin holes on both sides..... Victor what say you?

The hole is there, it is just not all the way through. No jig or extra work needed.....



The front driver in this loco is an original 3rd driver where the TT driver replaces. It has the same center in it and the center has a hollow behind the face that is crank pin sized. Just a small drill bit roughly centered in boss will reveal it.

Gearing the drivers has nothing to do with pulling power. It's more about reliability and spreading the work load among the drivers axles instead of the crank pins. I added an idler gear so that the front driver could be geared on my 2-10-2. This was before I realized that I could drill a hole in the wheel for the crank pin with relative ease. The loco didn't work well with the front side rods hanging free over two drivers. The slopped around much too much and there was a lot of risk of them catching the rest of the valve gear.

[superturbine]

The hole is there, it is just not all the way through. No jig or extra work needed.....



Awesome.... I did not realize that.  Thanks for the info, it will work great on the 4-12-2!

[squirrelhunter]

What Scale size are the drivers Bachmann used on their 2-10-2? Are they really 57" scale or are they like the 4-8-2 drivers where the measured off the flange, resulting in diver centers that are only like 52" and look slightly undersized?

[mmagliaro]

Chris;
Beautiful engine.  Yes, that really helps to know that the Con-Cor can work with a section removed from it.

Jason, pour in the brass?   
That's what I was wondering.   Is it that easy to get brass hot enough to flow so you can pour?  I thought that
was a lot harder than casting urethane.

[reinhardtjh]

What Scale size are the drivers Bachmann used on their 2-10-2? Are they really 57" scale or are they like the 4-8-2 drivers where the measured off the flange, resulting in diver centers that are only like 52" and look slightly undersized?

Bachmann Spectrum 2-10-2 drivers scale out to 54" tire size.  Driver spacing is an constant 63" between all 4 sets.

John H. Reinhardt

[fredmoehrle]

Fred -
 I'm curious how one would go about reverse-engineering a mockup for one of these for milling purposes.

Mike,
Usually it involves measuring the mockup all over with a vernier dial caliper and a depth micrometer.
If some things are know, like the axle spacing and the pocket depth, then that is that much easier.
One can just plug those numbers in and go with it.
I've thought about this for other things, and the real obstacle would be inside diameters for the motor mount, and if using a Atlas motor mount, the little square holes.
Once the programing is done, run cost goes down with the number of units run, with a base line of machine run time and operator handling cost with the setup/program cost amortized over the the above base line.

For example, John gives the center spacing of the drivers as 63", which is .39375" scaled down.
With the proper pitch diameters for the axle gears and the idler gears, plus the rotating diameters, a gear train could be designed.
With the bearing diameter of the drivers measurable, we get the basis of the critical dimensions for the frame.

The lost wax method could be a viable way to do it, just in my experience we still need stock left on for clean up, just because things can move in the casting process.

For the size of what's being talked about, free machining brass would just be easier, forgoing leaded steel.
I know back on the Atlas forum people talked about denser materials, tungsten and depleted uranium.
The problems with those are;
Tungsten: cost and hard to machine.  (There's a reason it was the primary component of anti-tank cannon rounds until the 1980s)
Depleted uranium: Cost, hard to machine (guess what replaced tungsten in anti-tank cannon rounds!), toxic, radioactive, government oversight.

I hope I'm not sounding to arrogant or anything, I'm trying to enplane processes I've observed for 44 of my 49 years on earth.

[mike_lawyer]

Mike,
Usually it involves measuring the mockup all over with a vernier dial caliper and a depth micrometer.
If some things are know, like the axle spacing and the pocket depth, then that is that much easier.
One can just plug those numbers in and go with it.
I've thought about this for other things, and the real obstacle would be inside diameters for the motor mount, and if using a Atlas motor mount, the little square holes.
Once the programing is done, run cost goes down with the number of units run, with a base line of machine run time and operator handling cost with the setup/program cost amortized over the the above base line.

For example, John gives the center spacing of the drivers as 63", which is .39375" scaled down.
With the proper pitch diameters for the axle gears and the idler gears, plus the rotating diameters, a gear train could be designed.
With the bearing diameter of the drivers measurable, we get the basis of the critical dimensions for the frame.

The lost wax method could be a viable way to do it, just in my experience we still need stock left on for clean up, just because things can move in the casting process.

For the size of what's being talked about, free machining brass would just be easier, forgoing leaded steel.
I know back on the Atlas forum people talked about denser materials, tungsten and depleted uranium.
The problems with those are;
Tungsten: cost and hard to machine.  (There's a reason it was the primary component of anti-tank cannon rounds until the 1980s)
Depleted uranium: Cost, hard to machine (guess what replaced tungsten in anti-tank cannon rounds!), toxic, radioactive, government oversight.

I hope I'm not sounding to arrogant or anything, I'm trying to enplane processes I've observed for 44 of my 49 years on earth.

Fred -

I did not address this in the original post, but I would envision slightly modifying the motor mount area from the stock Kato Mikado motor space.  Basically, I would make the diameter wider, about 10-11mm wide, to allow for remotoring the engine using a coreless motor.  This would eliminate any need for a special motor housing area.  It would also allow the locomotive to use the stock Mikado motor if one so desired.

The depth of the bearing blocks and the spacing of the blocks can be easily measured with a caliper. 

How much would this process cost?  I know it varies by how many units are made, but I'm just trying to get an idea of per unit cost based on a number of runs to see if this is something that people would be interested in.

[fredmoehrle]

Still a couple of variables to consider.
I'm at work, and don't have one of my Kato Mike's to dismember.
I really can't see more then an hour to 1.5 hours in programing and set up, and the free machining brass is like butter.
But are there extra tapped holes for mounting pony and idler trucks, getting the shell to sit on the frame, etc.
I guess I can take a look at one of mine tonight when I get home.
A foot of 360 brass 1/4 x 3/4 is $14 from McMaster Carr, should be able to get both halves from that, so material cost is covered.

[mike_lawyer]

Still a couple of variables to consider.
I'm at work, and don't have one of my Kato Mike's to dismember.
I really can't see more then an hour to 1.5 hours in programing and set up, and the free machining brass is like butter.
But are there extra tapped holes for mounting pony and idler trucks, getting the shell to sit on the frame, etc.
I guess I can take a look at one of mine tonight when I get home.
A foot of 360 brass 1/4 x 3/4 is $14 from McMaster Carr, should be able to get both halves from that, so material cost is covered.

Cool, let me know what you find out.  I also have a disassembled Mikado mechanism that we could use.

[superturbine]

Chris;
Beautiful engine.  Yes, that really helps to know that the Con-Cor can work with a section removed from it.

Jason, pour in the brass?   
That's what I was wondering.   Is it that easy to get brass hot enough to flow so you can pour?  I thought that
was a lot harder than casting urethane.

Max-
I dont do it.. id burn down my house.  I have a brass caster here in Texas thats a model railroader

[robert3985]

Max-
I dont do it.. id burn down my house.  I have a brass caster here in Texas thats a model railroader

I've got the full lost-wax casting foundry (spin caster, metal melter, burnout oven, vibratory table, wax injector, etc.) but it's all on shelves in my garage and I haven't set it up for the seven years I've been living in my new home.  However, I take Styrene parts, and my own wax injected parts to a local rock shop/jewelry store where they do small lost wax investment castings to get small runs and one-offs done for my own use.  I supply the brass from my own stock and they charge me $25 a "throw".  So far, zero failures and they're getting more confident at casting brass since doing my small, detail stuff since their stock in trade is casting silver and gold for jewelry.

What I'm saying, is...if you don't have a captive model railroader who happens to cast brass, try calling local jewelry stores, rock shops etc., to see how much they'd charge to invest the urethane part and spin/vacuum/steam cast it in brass.  Like me, you'll probably have to supply the brass, which you can buy from a local foundry who does bronze nameplates for headstones, monuments etc.

One thing, ask the caster you choose if their investment is fresh.  Old investment will give you a distinctly grainy surface, whereas fresh investment will give you a surface very close to whatever you invest and burn out.

[superturbine]

Great advice Robert.. thanks

[wcfn100]

Another option could be someone who makes belt buckles.   Some of those are lost-wax spin cast setups.

Jason