Author Topic: 3D Printed Northern Pacific 52' flat car.  (Read 790 times)

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wcfn100

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3D Printed Northern Pacific 52' flat car.
« on: February 12, 2017, 11:37:19 PM »
+1
I received my first NP 52' flat car print from Shapeways and overall I'm pretty happy with it.





I messed up the coupler height due to the same mistake I fixed on the coupler gauge.  I really need to find a way to add weight along with something to help with warping.  My first though is some sort of L or C channel I can lay along the top of the center sill and glue the frame to it.  Another option is to etch the floor from .020" brass and glue to that.  It doesn't put the weight where I want, but it doesn't require a change in the design.

I have to see what sort of artwork I have to make a decal this week.


Jason


wcfn100

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Re: 3D Printed Northern Pacific 52' flat car.
« Reply #2 on: February 13, 2017, 12:58:17 AM »
0
1/16" tungsten welding rods.

Cheapest I could find: http://www.ebay.com/itm/1-5-Lanthanated-Tungsten-Electrodes-Gold-1-16-x7-tungsten-rod-for-tig-welding-/122305628869?hash=item1c79fbcac5:g:pLgAAOSw8oFX0IyP

That would be good for weight for sure but I'd have to make space for it.  I have a 3/64" brass rod that I had to file a bit narrower to fit between the center sill.  Doesn't add much but I can run it with several heavy cars behind it without any issues.  I need to swap out the Atlas wheels for metal ones and see what it takes to stringline this car on a 15" curve.

Jason

narrowminded

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Re: 3D Printed Northern Pacific 52' flat car.
« Reply #3 on: February 13, 2017, 01:33:42 AM »
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Those electrodes come in .040" too.  Basically twice the weight of brass.  Hard as hell.  Score it and snap it to cut then dress the ends.
Mark G.

Lemosteam

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Re: 3D Printed Northern Pacific 52' flat car.
« Reply #4 on: February 13, 2017, 06:31:14 AM »
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What direction(s) were the warp in?  Twist, bow (lengthwise) or cupping (like a 2x8 looking from the end)?

Any pics of it before?

Sokramiketes

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Re: 3D Printed Northern Pacific 52' flat car.
« Reply #5 on: February 13, 2017, 09:24:36 AM »
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Make the whole thing a brass casting, of course. 

http://www.best-cast.com/    :D
Mike

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Lemosteam

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Re: 3D Printed Northern Pacific 52' flat car.
« Reply #6 on: February 13, 2017, 11:33:03 AM »
0
Make the whole thing a brass casting, of course. 

http://www.best-cast.com/    :D

Just had this done at Shapeways, part was just under 3% too small in every dimension.

wcfn100

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Re: 3D Printed Northern Pacific 52' flat car.
« Reply #7 on: February 13, 2017, 03:17:12 PM »
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Make the whole thing a brass casting, of course. 

http://www.best-cast.com/    :D

I did look at that after you had previously posted it.  I'm not sure my design could even be two-part molded plus I think all metal flats are too heavy especially if you plan to load them.  Also, I only need one or two cars, I can't imagine it's cost effective to only do a couple.

With all that said, once I make couple changes and get back one more print to check, I'll probably send it to that company and see what they say.  And once I get a finished car, if people are interested, I can try and change the coupler to a standard MTL compatible coupler and box and look at more of a production situation.


Jason

Sokramiketes

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Re: 3D Printed Northern Pacific 52' flat car.
« Reply #8 on: February 13, 2017, 03:52:25 PM »
0
Just had this done at Shapeways, part was just under 3% too small in every dimension.

While Shapeways won't work with you to figure out the proper scaling factor, Best Cast will. 

Mike

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Sokramiketes

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Re: 3D Printed Northern Pacific 52' flat car.
« Reply #9 on: February 13, 2017, 03:55:33 PM »
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I did look at that after you had previously posted it.  I'm not sure my design could even be two-part molded plus I think all metal flats are too heavy especially if you plan to load them.  Also, I only need one or two cars, I can't imagine it's cost effective to only do a couple.

With all that said, once I make couple changes and get back one more print to check, I'll probably send it to that company and see what they say.  And once I get a finished car, if people are interested, I can try and change the coupler to a standard MTL compatible coupler and box and look at more of a production situation.


Jason

The beauty of a rubber mold is that it can handle everything I'm seeing in the photos so far.  Remember, they were able to do it with stirrups on my flat.

But yes, the first one will be a couple hundred bucks, so if you only need two...
Mike

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wcfn100

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Re: 3D Printed Northern Pacific 52' flat car.
« Reply #10 on: February 18, 2017, 12:59:11 PM »
0
I spent some time this week trying to see how to add weight and straighten the frame and I think the easiest solution is a .016" brass deck.  But because I'm impatient, I went ahead and added a .020" stryene deck to see what it might look like.  I also grabbed some sill steps off a MTL stock car.



I've got some metal wheels for the Atlas trucks on the way.  With those and a metal deck, I don't see the need to add more weight until there's a problem.  Even at the scant .2 onces it is right now with plastic wheels and deck, I have no issues with it tracking.   I also have some brake wheels on the way to try out and I need to get my hands on MS sheet 60-777 so I don't need to print out decals.

I think I'm almost ready to make another print.  I need to lower the coupler and enlarge all the holes I made for grab irons because they all got lost.  Might try my hand at making a lumber load in 3d to go with it as well.


Jason

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Re: 3D Printed Northern Pacific 52' flat car.
« Reply #11 on: February 18, 2017, 02:02:06 PM »
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That would be good for weight for sure but I'd have to make space for it.  I have a 3/64" brass rod that I had to file a bit narrower to fit between the center sill.  Doesn't add much but I can run it with several heavy cars behind it without any issues.  I need to swap out the Atlas wheels for metal ones and see what it takes to stringline this car on a 15" curve.

Jason — get the center of gravity below the horizontal centerline of the coupler.  Then you'll drastically reduce the possibility of string-lining regardless of the weight.  The GSC well car is only 0.4 ounces, and I've pulled and pushed 1½ pounds around 10" radius without even lifting let alone derailing.  Using a tungsten fishbelly centersill and a laser-cut plywood deck should be enough to accomplish that.
Bryan Busséy
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wcfn100

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Re: 3D Printed Northern Pacific 52' flat car.
« Reply #12 on: February 18, 2017, 02:17:54 PM »
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Jason — get the center of gravity below the horizontal centerline of the coupler.  Then you'll drastically reduce the possibility of string-lining regardless of the weight.

That's what I'm hoping the metal wheels will provide.  The metal deck isn't ideal but I think it's going to give me rigid enough surface to glue the frame to and keep it straight.  It's just too easy of a solution to pass on.

Is for weight, I've openly expressed my view that.  NMRA would want this car at over an once which is totally unnecessary.


Jason

wcfn100

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Re: 3D Printed Northern Pacific 52' flat car.
« Reply #13 on: February 18, 2017, 05:12:58 PM »
+5
One more update for the weekend.  I went ahead and free drilled the end grabs and used a MTL horizontal brake wheel I had around (not what I'm planning on using but it's not bad either).  The air line will accompanied on the under frame by the valve, cylinder and reservoir hopefully later this weekend.  Once those are placed, I should be good to update the drawing.




I'm considering adding a BLMA cut lever just to see what it looks like, but not sure I want to open that door.

Jason