IF someone were to develop a chassis system with reliable drive components, semi flexible arrangements and replaceable parts, how much would you be willing to spend?
Do you mean a drivetrain, or a chassis with drivetrain, with suspension, etc.?
They did! It was called a BBT drive
@Greg - That is kind of what I started this for. What is it people are looking for? Barry made a bulletproof drive, but in only one configuration (for a 6 coupled and one for an eight coupled). Would there be an interest in other wheel arrangements / spacings / diameters? Is a suspension a requirement, or a rigid chassis acceptable? How much motor would be preferred? How important is scale speed at full voltage, and what should that voltage be?
Where these lines are drawn affects what can be done and at what cost. Without additional input from modelers I don’t have a reference point to even evaluate 'does this warrant investing the time to research further?"
!Dave - That is absolutely correct, providing those two drives are all you will ever want.
If you are looking for a modular drive system, you could use the Aristo one, and then put straight axles on to support different wheels…
You could limit side to side travel if you wanted, or make drivetrains with hinged siderods to allow all flanged drivers.
But your bigger issue would be different chassis with different axle spacing… and you would want a suspension… that would really call for customization… laser or waterjet cut chassis halves.
Don’t think the cost would justify the expense.
Bashing Aristo chassis has been successful to an extent, I have a 4-8-4 Northern and a 2-10-2 Mountain built this way.
Greg
You know… this question makes me think of those snap-together modular systems in all the toys released over the years. In this case, I’m thinking of the motor as one piece, each axle/gearbox is one piece, and there are two different size spacers available to put between axleboxes, giving at lease 4 different axle spacings (none, small, large, small+large). This design I could have a mogul or tenwheeler with the two lead drivers closer together than the third axle to second axle. Also possible to do the trucks for the old Alco six-axle units.
If the modular powertrain couplings could be done well enough, each gearbox should have the reliability of LGB’s drives.
I would think this would allow a minimum of part designs, with a maximum of drive system options.
JD - That was the target. A one from column A, two from column B, and so on until you had a complete driver for what ever configuration you desired.
I was sort looking toward the old days in O scale where there were always several detail vendors where drivers, cross heads, etc were available for scratch/kit-bashing. With modern SLA technology, I would think it would not be difficult to establish a library of parts. There are several good vendors available to do short run castings in brass or other materials.
I have not received the response I was hoping for, so I guess there are not that many interested in other than bashing what is already there.
sigh
Bob C.
What it would be worth and what I could afford are two different things. If I understand it right the concept is a great idea. Probably above my building level though.
This might be a good project for 3D printers. Print a drive train in plastic, space the axles as needed for your particular wheel arrangement – equal spacing, unequal – whatever.
Rescale the drawings as needed. Why, you could even make 1:32 narrow gauge equipment that is actually smaller than standard. What a concept.
You could install metal wheels and axles after the 3D printer is finished with the gear box. Install gears and the motor. It should work.
After I get my 3D printer built, I’m going to do simple stuff. But it does seem to me that a plastic chassis like BBT built out of metal should be fairly simple. A U-channel with holes for axles and spaces for motors.
@Dick, My experience ( limited) is that the stuff printed my most “Low End” printers is not very durable or tuff. the finnish on the printed stuff, is not very smooth, unless it is sanded and polished out, and then you would have to add to the product size when printed to compensate for the material removed in the polishing out. I don’t know if the plastic that is available for the printers and be interchanged for a harder/durable product.
Making RTV molds from unfinished patterns, presents a few challenges, due to the micro ridges created by the printing process.
Hopefully some one here with more knowledge then me can help you work thru the pending challenges.
Terry Burr said:
What it would be worth and what I could afford are two different things. If I understand it right the concept is a great idea. Probably above my building level though.
Don’t know unless you try Terry!
I’m getting there slowly 
Dave - To the best of my knowledge you are correct in principal. I have talked with a professional here in central Florida, and he tells me there are resins for the higher dollar machines that are near as good as some soft metals.
Dick - I was attempting to see what others would ‘like’ to see. If there is enough similarity on even two or three fronts it might be worth persuing.
Modeling in 3D solids makes all of this so much easier than having to ‘manufacture’ parts in real material to determine if an idea does not really work. It also allows strength testing, making parts lighter/smaller.
Bob C.
@Bob My point exactly… Most of us can’t afford the High $ machines, and the low/mid cost Machines will produce good stuff but you have to work within their limits. Testing a concept, is a good use of these printers. But great quality and precision for a production basis, or even making molds for production would be very really difficult to achieve.
Bob,
The next issue you face is getting the rods to work at the exact spacing of the frame.
One of the biggest inhibitors for building locos is the lack of wheels castings. I built a 2-8-0 using ‘conventional’ O-scale techniques - plate brass frames soldered together (so they come out identical,) drilled and cut. But it only worked because the Bachmann 4-6-0 wheels were the correct size.
NG wheels have fewer spokes than SG wheels, so there’s another complication for the wheel supplier. Slaters in the UK provides lots of different wheels using plastic/nylon spoked centers and stanless stell rims - might be a way to go? On the other hand, the chinese are good at casting brass wheels.
Making a frame (or having one cut) isn’t difficult. Motors and gearboxes are available. But we don’t have wheels and we don’t have coupling rod stock.
I have built the 4-6-0 drive, both rigid and front axle equalized and 2-8-0 in the same option.
Also have built Trolley drives, up to this time hand laid out, but am building a drill jig, so these can be built with a little more precision.
Have built many Porter drives, both stock and shortened chassis.
Also, repowered a U-25 with two Pittman motors, a powerhouse!
Will be taking a look at repowering the Gandy Dancer (we’ll, see).
Also several Beyer-Garrett locos and/or drives.
Have a drill jig for C-16 chassis in 20.3, have done a couple of these.
What do you want?
Barry
Well, I’ve wondered for some time concerning rod engines:
What if each axle had a small motor and gearbox so you didn’t have gears and shafts connecting each axle, just the rods? Then you wouldn’t have to worry about one axle being ahead or behind of where the rod demands it be. If the rods were trying to push one axle ahead a little bit, they’d just speed up the motor a hair, not fight the gearing and shaft.
I’m not a mechanic, but it seems if you have 2 “things” forcing the relationship between moving parts, you’re subject to binding. Well, in locos with all the axles driven, you have 3 things trying to force the relationship between moving parts: Right rod, left rod and motor shaft.
Of course, the whole discussion simply doesn’t apply to geared locos or diesel electrics.
“wondered for some time concerning rod engines”
Tom,
That’s not the problem. If the holes in the rods aren’t exactly the same distance as the ones in the frame, the wheels won’t be able to turn properly. Most binding seems to come from rods that aren’t perfect.
Add to that the need for suspension, and you are facing a complicated rod with multiple joints. Yes, manufacturers usually manage to make them work, but it can be tricky for a scratch-builder.
The conventional way to do it in HO or O scale is to fasten the two rods to the frame pair and drill all 4 pieces with the holes for the rods. Then you re-drill the frame on the same centers for the xles, if they are larger.
A long time ago in a scale far smaller, a close friend and scratch builder of real On2 built his Forneys by first soldering the two frame side pieces and the blank rods together in one solid piece. He then laid out the centers on the rods (which were soldered to the frames) and pilot drilled all four pieces at the same time. This guaranteed the hole alignment within a few thousandths of an inch. After de-soldering the stack, he then pinned the frames together and re-soldered, as well the rods, later drilling the frames and rods to their proper sizes. Next time I am at his son’s place, I will take some close ups of the completed engine to show it can be done without high end machine tools (although they make it much easier).
John’s were all rigid frames, but I am sure there could be a method to do an equalized frame is a similar manner.
Bob C
FWIW - These models were built in the '60s, '70s and early '80s.
You may not have noticed, but perfect alignment never stays that way