3D printable traction motor case

To give a bit of an idea what I was going for this is the complete unit:

View attachment 303582
It sounds like it is broadly similar to what you describe. The key difference is that instead of having the axle boxes move individually the side frames are a single piece and twist relative to each other. The left cross member has a single screw on which it tilts laterally, the right one is rigidly fixed to the car body. The side frames are held to the cross members by an M2 screw at each end. The central cross member is not fixed to the side frames, it just supports the back of the traction motor cases.

The holes in the cross members are all designed to line up with the existing screw holes in the bachmann tram car body, though some shortening of the plastic mounting posts will be needed to get the floor height right.

The reason why I went for a rigid side frame rather than separate moving axle boxes is it allows the use of a small flanged roller bearing in the axle boxes, as well as making the whole thing a lot stiffer for printing in PLA. For my printer at least I think the side frames need to be separate parts so they can print inside face down on the table. I could potentially make a version with the sideframes rigidly fixed to the cross members and separate axle boxes, though I'm not sure what orientation you would print it in to make sure everything was fully supported. I would think it would probably need to be ABS too, just because without the axle boxes in place (and presumably the primary suspension springs?) the frame on its own is pretty thin.



Hopefully this answers that as well.

I was going to wait until I've had a chance to print and test fit a prototype to make sure everything lines up properly before uploading to thingiverse but the sideframe on its own is attached if you want to see if you can make it fit your purposes.
I know this is an old thread, but was the complete unit ever uploaded to thingiverse? I'm finally getting around to fixing the Bachmann tram. Thanks,
 
I know this is an old thread, but was the complete unit ever uploaded to thingiverse? I'm finally getting around to fixing the Bachmann tram. Thanks,
You can find it on thingiverse, or in the thread further down the front page of this forum.

 
Entirely a personal preference, I prefer the KW Trams G scale truck, this isn't a diss on Melbournesparks' truck side simply a personal preference, largely I suspect because I was use the KW Trams truck side first and it's easy to fit springs.

For a traction motor I have no reason not to continue using the traction motor, my only warning, and probably because I'm heavy handed, is care when cleaning up the matting faces of the two half's, on one of mine I ended un gluing a thin piece of emery paper on one end, nothing to do with the traction motor casing, entirely yours truly being heavy handed with a file.

Excellent design and I am extremely grateful that Melbournesparks took the time to design this and share freely with us.

Just to also note, I have a pair of these trucks in one tram operating off batteries, the truck in the photo has been run on straight DC and on DCC (which I am switching over too). When you order the motors double check what voltage rating the motors are for, I nearly ordered 3v motors which wouldn't have been clever, I played around a wee bit when I ran a truck on DC, it definitely ran better when wired in parallel rather than is series which had been my plan.

One thing to note with the trucks, you'll notice I have a piece of brass H section soldered to the top of the truck, this was just to raise the the tram body height slightly, which is still lower the the original body height, lowering the body definitely improves the look of the tram.

Glad to hear someone else is tweaking their Bachman tram.


David
 

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You can find it on thingiverse, or in the thread further down the front page of this forum.

Thank you! I was looking under G Scale. Looks like I'm going to have to include 1/24 Scale in my searches now. I should have known searching for anything "G Scale" would be as convoluted as eBay!
 
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