Need to replace Accucraft 2-truck Shay's truck frames - 3D print?

[Mark Janzen]

I have a narrow gauge 1:20.3 Accucraft electric 2-truck Shay #2. The existing pot metal frames on both of the trucks are damaged beyond repair. I would like to 3D print new truck frames and use the existing gearing and drive shafts. I only know how to use TinkerCad and TinkerCad is not sophisticated enough to design the required STL files for my PRUSA printer. Due to 3D printer filament structural limitations,I realize the new plastic truck frames will need to be more robust and not true to original truck designs . Does anyone know where I can find suitable shay truck design STL files? I'm willing to "tweak" a related Shay truck designed. Any help would be appreciated.

 

[dunnyrail]

I have a narrow gauge 1:20.3 Accucraft electric 2-truck Shay #2. The existing pot metal frames on both of the trucks are damaged beyond repair. I would like to 3D print new truck frames and use the existing gearing and drive shafts. I only know how to use TinkerCad and TinkerCad is not sophisticated enough to design the required STL files for my PRUSA printer. Due to 3D printer filament structural limitations,I realize the new plastic truck frames will need to be more robust and not true to original truck designs . Does anyone know where I can find suitable shay truck design STL files? I'm willing to "tweak" a related Shay truck designed. Any help would be appreciated.

Personally I would be making from metal using silver solder at the start and soft solder for less structural parts. Thin strip brass or nickel silver would be ideal material and be surprisingly strong and long lasting.

 

[Fred2179G]

First, email Ryan at Triple R Services (About TRS | Triple R Services) who is my local Accucraft dealer and an ace repair guy. He's familiar with the problem and may be able to help.

I would investigate whether the trucks on the new 13T shay are available. If so, I suspect they will fit your loco with a little fiddling.

 

[Gerard]

I have good results with 3-D printing as long as you be aware of the difference in strength in the filament direction and across the filament direction.
It is like you deal with wood, in the length direction of the fibers it is strong but across it is much weaker.
Problems with this strength difference can be solved by breaking up your 3-D print design into separate pieces that can be printed on the flat base plate having the filament directions always in the direction that has to be strong.
There is one more condition when breaking up the design: the filament printing must always be on top of previous printed filament. This means that you have to (re-)rotate parts of your desing so that they can be printed without any support.
You can easily make this separation into pieces in Thinkercad by removing part of the design using a transparant block and use the "Group" option (Ctrl+G) to end up with the separate piece of your design. Next you have to rotate this piece in a proper flat printing position on the base plate.

I used this method for example succesfully when printing a model of a snowplow or a light tower.
See below some examples of printable seperated pieces of the design.

 

[Steen Rudberg]

I just replaced mine with some metal casted trucks.
They are DCC ready.
Now I just have to remember where all the screws are to go....

 

[Mark Janzen]

Where did you get the metal truck frame castings?

 

[Gerard]

You can build very sturdy structures for your model: use plastic "print plate" material. It has two sides covered with a thin layer of copper. You can easily cut or saw the flat shapes of your model using a small model sawing machine and later solder these pieces together as if you are welding plates together using a narrow solder line at bothe sides. This create a very strong structure that also looks like a real steel structure. See pictures example of a (head down) single teststand for checking a locomotive and a close up picture of the solder connection

 

[Steen Rudberg]

I'm building a 3rd unit from one for the old defective motor blocks.
It will have power pick-up

and - yes there is a fault in the block....