# My first 3D model!



## Shdwdrgn (Dec 23, 2014)

We have a pretty nice 3D printer at work which I have access to use, so over the past year I've found different CAD models online that I could print out. Recently I started printing some servo mounting brackets for turnouts, however everything seems to have a larger hole than the screws that come with the servos.

I've poked at a couple different CAD programs, tried to figure out the overwhelming number of controls, gone through their guides... it just seemed like one of those things that I would need to burn a week just to figure out the basics. Well I needed to make these screw holes smaller, and someone had mentioned "Tinkercad" to me. OK so I gave it a shot. Well the first thing is, this isn't software for your computer, it is a web-based program. As someone who has written a lot of web software, this thing is *impressive*! Full 3D rendering right there on your screen, and the controls are kept very simple and intuitive so I was able to dive right in. It took me about an hour to figure out all the controls and get a plug made to reduce the size of the screw holes. A couple of test prints and I had the size just right that the screws made a good snug fit. Hooray!

Inspired by the ease of this program, I pulled out another project -- a 40' HO flatbed that printed up fairly nice, but has absolutely no weight at all. What I needed to do was cut a rectangle out of the bed where I could drop in a steel plate and then cover with the wood bed. A bit of fiddling and I had the original model cut up, leaving just enough room for the coupler screws but allowing for a good solid 1/16" plate to be dropped in.

Looking at that flatcar got me to thinking... I could use a basic framework for an old wood-frame narrow gauge flatcar. This should be easy to model, I think? Well, it was! I found a couple blueprints for a 28' flat, made some measurements to get my scale size in millimeters, and started making beams. This tinkercad software is real easy to work with. If I need a square beam, I plop down a new block on the floor, then change the dimensions to make my full-length beams. Add the end beams and move them so they intersect the long beams, creating a solid joint between the pieces. Add the bolsters and a couple of queen posts, and it looks really good so far! I pulled up the Kadee site to get the dimensions of their couplers, and them cut out a slot in my drawing for them to sit in. Not nearly as much meat to work with on a narrow gauge car so I only cut a hollow for a 1/32" weight plate on this one. Finished by printed out one copy to bring home so I could see how everything fit.



















The grey car is a Rail Line kit I made awhile back. That car is about 32' long while mine is 28', but otherwise both narrow gauge. The size of my frame appears to be right on the money. The kadee coupler pocket fit perfectly in the slots I made, but I forgot to leave a solid piece to put a screw through. The bolsters are close, but I need to add a center point to raise the truck exactly 1mm, which will give it the clearance to turn without the wheels hitting the frame. I might also widen the bolster in the center to provide a bit more material for the truck screws. Once I have the truck height set, then I can adjust the position of the coupler slots so they sit at the right height.

All in all, not bad for my first try. I intentionally did not add a lot of detail to this model because such tiny features don't print well, or at all. The stake pockets can be added later, along with the tension rods, grab-irons, brake details, etc. I just wanted an open framework as a starting point, then I could slap on the trucks, couplers, and a weight, and have a whole fleet in no time just waiting for detailing and paint.

I'm really excited about how this model is coming along, and the cost to print each of these frames is literally just pennies. I might even add the larger brake parts into the model. This just opens up a whole new world of things I can do now!


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## wvgca (Jan 21, 2013)

it's good that you finally got going on this, lol


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## Spence (Oct 15, 2015)

Pretty amazing. 3-D printing certainly opens a new world to model railroading.


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## Vincent (Jan 28, 2018)

Very impressive!


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## gunrunnerjohn (Nov 10, 2010)

Neat, I'll have to check out Tinkercad.


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## Shdwdrgn (Dec 23, 2014)

Once I get closer to a final version, I also have a spool of a milky semi-transparent color that I'll use. That color I think makes a good base to paint over. The details of the printed frame don't come out crystal-clear for small scale (think of it like building a shape using small fishing line), however with a little bit of filing I can square up the edges. It would be nice if I could include the stake pockets in place, but we haven't worked out yet how to get that fine of detail out of this printer.

One thing I do need to play with still is checking to see if there are any problems gluing styrene to this type of plastic with the standard glue. I'm not expecting any problems, but hey, you never know.


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## Shdwdrgn (Dec 23, 2014)

I've been looking into the weight of the car today, and determined that it's going to be just about impossible to get the unloaded car up to the NMRA-recommended 2.25oz. In fact I don't think I can get it even close to that. Weighing the frame with a pair of trucks (plastic truck, metal wheels) gives me. 0.2oz. With the space I recessed to put in a metal plate, steel would add another 0.29oz and lead would add 0.4oz. Even if I doubled the thickness of the recess for a lead sheet (which would barely leave the long support beams visible), I would still just barely reach one full ounce of weight. Yikes, that's a light weight car!

I did think of one possibility though. Instead of trying to recess a metal plate into the floor, I could make the deck itself out of lead, or maybe use both to really bring up that weight. I was hoping to maintain the details of the underside of the car so that might work and at least get me close to a desirable weight for the cars. Too bad we don't have the technology yet to 3D-print the entire frame out of metal, that would certainly add some weight.


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## Shdwdrgn (Dec 23, 2014)

Been making some slow progress on this. I have a raised pad to set the height of the trucks now, and got an eyeball measurement for the height of the couplers last night. I also added holes for the trucks and couplers, undersized so they could be drilled out properly or tapped for a threaded screw. Tonight I'll try putting it all together and see if I need to adjust the coupler height to match up my my gauge, but at this point I'm down to 1/10th mm increments.

There's one bit I'm still having trouble with. The car is printed upside-down, and the recessed slot for the weight plate causes some of the beams to float above the surface of the plate. While printing you need to have supports for everything that isn't touching the plate, but unfortunately the supports seem to end up stronger than the car beams, and I keep tearing those beams while trying to remove the supports. I've been trying to figure out a solution but so far haven't had any luck.


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## wvgca (Jan 21, 2013)

? do you have a link to the tinkercad file for the flatcar ??


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## Shdwdrgn (Dec 23, 2014)

I *think* this link will get you there?

https://www.tinkercad.com/things/9SY6Gx3hlzO-drgw-ng-30-flatcar

[EDIT] I should probably also add links to the two blueprints I used for all the measurements...
http://lsc.cvsry.com/EBTTank/Wood_Flat_102.jpg
https://model-railroad-hobbyist.com...bbyist.com/files/users/Rick M/Flatcar.jpg?317

There are some differences between the dimensions given, but once scaled down those differences are smaller than my print resolution. I ended up making the bed 7'0 wide and 28'0 long, not counting grabirons and stake pockets. The cross beams at the front and rear are 7'6 wide. I measured the sills as 8x10, the end crossbeams at 6x8, and the other beams at 4x8. Of course those images aren't the greatest for detail so my measurements could be off.


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## wvgca (Jan 21, 2013)

thanks .. link works fine ...


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## Shdwdrgn (Dec 23, 2014)

Bad place for a page jump, but note that I edited my last reply to also include the drawings I used for the dimensions.


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## wvgca (Jan 21, 2013)

looked at your drawing on tinkercad .... the queen posts don't seem right ...
aren't they supposed to be a little like a wedge shape ?? a little wider where they meet the main beams ..
slowly getting used to tinkercad, takes a bit, lol ... easy enough to widen from 1.17mm up to say 1.5 ??


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## Shdwdrgn (Dec 23, 2014)

Hmm that's a possibility, and I can certainly add that. The drawings didn't really give any indication about the height of the supports that hold the tension cables above the queen posts or I'd try adding them into the drawing as well (although that may be too fine of detail for what can actually be printed).

Got in a sheet of lead yesterday for weighing down the cars... Unfortunately I ordered 1/32" thick and they sent me 1/64", so waiting on a reply from them. I can certainly use both sizes, but I had cut out the plates for the car and wondered why it still didn't weigh nearly what I expected it too.

I'm working the model towards a 1/16" recess in the frame, and plan to use a 1/32" sheet of lead for the bed itself. If I can get that to work the car should come in at 1.68 ounces. Still shy of the NMRA target 2.25 ounces, but at least the car will have some decent weight even without a load.


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## Shdwdrgn (Dec 23, 2014)

Actually I think the queen posts *should* remain square. I've been digging through more images, and everything I found should a regular rectangular beam for the queens, with the hardware for the truss rods mounted underneath them.

https://www.gutenberg.org/files/49341/49341-h/49341-h.htm

Great old catalog I found, there's a section on flatcars about half way down. I was excited to find a large section on skeleton logging cars right above that as I also need that information.


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## Shdwdrgn (Dec 23, 2014)

So I did my first full test with wheels on the model tonight. I dragged a file lightly across the face of where the wheels sit to make sure there weren't any burrs, then tapped the hole. Nice fit with the Micro-Trains trucks, they spin nicely on their seat without catching. The wheels don't spin as nicely as the Kadee all-metal trucks I have, but they worked fine for this car. (Sorry the picture is so dark, I don't have a lot of light available there.)









It's actually got a much better turning radius than I thought it would! Keeping in mind that this is narrow-gauge, and might possibly see some use on a logging line, I wanted to know how tight it would go. I formed the track around a 22" barrel (11" radius) and it didn't even struggle. So I found a bucket and formed approximately a 5" radius curve. Ugh, just a little too tight. I opened up the curve a little more and then the car was able to go stay on the track. I think this car could reasonably handle 8" radius curves if it had enough weight on it to keep from being dragged to the inside of the curve.









I checked the coupler height once more, and it's almost dead on target. Maybe slightly higher than the gauge, but a little more work on the mounting posts for the wheels would bring that down for anyone who is a stickler.

You might be able to see in the first picture that the brass is not quite flush with the edge of the car. Apparently the pocket still isn't a full 1/16" deep, however the lead sheet might be slightly less thick than specified (and the brass might be over-sized), so I'll wait until I get another sheet on hand and test again before making adjustments to the pattern.

All in all, I'm pretty happy with how it's coming out. I think I might go ahead and order some Kadee trucks though. Besides running smoother they also have a metal body and will bring up the weight just that small bit more. The Kadees are a royal pain to assemble, but they do look a lot nicer.


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## wvgca (Jan 21, 2013)

if your research shows he queen are square , we'll go with that ...,lol
i am pretty new to the 3d world, just got a 'kit' which requires assembly, lots of it ...but i wind up with 220x220 mm, so big enough for the little bit i need .. it's a prusa i3, and i was the only bidder, came out of toronto so shipping was pretty quick ..
just going to do PLA from the start ..
and cura for the slicer software, still using inventor for the stl files ..


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## Shdwdrgn (Dec 23, 2014)

Well 'research' might be a little strong. I browsed google images looking at pictures of original D&RGW narrow gauge flatcars, plus a few blueprints and the catalog pages I linked to. Does that count?


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## wvgca (Jan 21, 2013)

well, it's more than I've done, lol
So far I have made several dozen flat cars in the old 1890 style, 26 or 28 foot long frames, but at first used strip wood, then CNC routed the frames , no 3D to date ..
I only got the 3D kit yesterday, and probably half the parts are still loose on my kitchen table, soon soon ... yeh, yeh


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## Shdwdrgn (Dec 23, 2014)

I'm not expecting a lot of high detail with these prints, they certainly won't win any shows. However it does allow for the chance to build up some rolling stock rather quickly since I have nothing in narrow gauge yet (I haven't even finished building my 2-8-0 loco kit). The biggest problem will be the stake pockets, however for those I might just grab some square styrene tubing and chop off pieces to glue to the sides.

I really want to try laying out one of those skeleton lumber cars now. I previously made one with styrene but it was just SO light weight. Solid brass might be my only suitable option for that guy, but at least I have some good blueprints to work from now.


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## Dennis461 (Jan 5, 2018)

Lead weight for log car can be inside the frame or a single log


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## Lemonhawk (Sep 24, 2013)

PLA is easy to use (in a relative manner) My first attempt at PETG worked fine, but the second load of PETG I could not get to stick to the bed. So PETG is a bit finicky. I think the 3D printer kits are a nice way to go as you learn something about the inner workings of the printer. To me, the most amazing thing is that once started the printer will run for a day, open loop, for all the mechanical movement! When I went to school we studied 2 phase servo motors and amplidyne generators! Without feedback they were worthless.


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## wvgca (Jan 21, 2013)

i'm okay on the log cars, bought quite a few of the ?? cars on ebay, [new ones are wiseman], just added Kadee couplers and Tichy archbar trucks with Intermountain wheels ...


Need more of the 28 foot flatcars, they don't seem to show up very often at all, this is a good excuse to get a 3D printer for myself ..


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## wvgca (Jan 21, 2013)

had an idle thought .....


what if you made the steel or lead weight the same size as the deck... that way no fiddling, or not as much , and it would be easier to print, a little anyways ?
basically no cutout to worry about ??


[need some blue painters tape for project 3d printer, lol]


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## Shdwdrgn (Dec 23, 2014)

Do you mean keep the top of the printed desk flat to set the metal on? The thickness of the frame is only about 7/64", and I'm adding 1/16" of lead inside the frame, PLUS another 1/32" of lead on top to make the actual wood deck... and all that still comes up short of the target weight. If I were to add that 1/16" plate on top of the frame it would make the frame noticeably tall.

Or did you mean something else?


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## wvgca (Jan 21, 2013)

no, basically i meant that , didn't realize you were adding more lead already ..
have to measure the ones i have already done ,, seem to think they were a bit larger ??


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