GSC drop center flat HO 3D print SL-SF, AT&SF, CR

gjslsffan Jun 21, 2019

  1. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    What I’m worried about are the finer details not really printing and just kind of looking like a blob, especially on the ends. The freestanding parts like the cut lever bracket look to be very fragile and could be ill-formed once it is printed. It already looks kind of chunky, and it is at the lower end of Shapeways’s recommended size.

    I am primarily using the brasstrains photos of the car to do the end details, since the prototype photos don’t show it. They are kind of vague, especially around the brake wheel brackets. I’m not sure what the lower one is supposed to do, but gluing a lower end bracket from a Tichy brake kit might be a good idea. (Parts 23 and 24) I can do a blanking plate or something to keep the brake wheel stem from falling through, but I don’t know what the actual detail is supposed to look like, and I doubt it would print accurately anyways.

    The upper bracket probably has a ratchet wheel on it, and I can guarantee that that will not print. I can do a small ring around and hope it prints just to represent it, or the Tichy kit has one you can chisel off another part if you really want to have it. I have an air hose support with a hole to drill out, but I don’t know if you need it. You can probably file off some of these details and remake them as needed.

    Otherwise, the coupler height should be within 1 scale inch if you put the box right in that cut out below the anticlimber. Would you glue the box or use the screw hole? I am worried that the screw would come all the way through the deck. If you want a pilot hole for the coupler box, I can do that. Your wood deck should cover it if the screw comes through. Just file it flush and you’re good to go.

    Regarding the trainline hose, I think it would look good as brass wire, but you might have to do it in sections. On the prototype, it passes behind the jacking pads, but since the car ends block off both ends of the car, it would be super hard to feed it through any holes I put through them. You could cut a section of wire that stops at both pads, and then more wires on either side, so it looks continuous, without actually being so.

    OR

    I make the jacking pads separate, and then they are glued on after the air line is installed. These could be made from styrene square tube stock too, not just printed. The grab irons could benefit from NBW castings if you wanted them. Again, the print would probably be worse than the Tichy injection parts. image.jpg
     
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  2. gjslsffan

    gjslsffan Staff Member

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    I have Tichy stem winder brake details on hand, so let us not deal with that, if you could instead of having that bottom brake detail toward the bottom instead go towards the front, then I can drill thru the Tichy part thru the printed boss and that would be great. The brake wheel is what keeps the staff from falling thru. These stem winder brakes are the worst hand brakes ever. The staff does have a ratchet type mechanism on the top side. It has a brake wheel that is too small to apply any real force to the brakes by hand. That is why brakemen carried a brake club to use as a sort of cheater bar, to set these type hand brakes. Problem was, the only way to release the brake was to wind it a little tighter, put your foot on the ratchet to hold it open then simply hold the brake club up right, and let the brake wheel spin to release the brake, now this presents a problem in-that if you dont hold the brake club upright the club will spin around and smack you, dont ask how I know that BTW. It is for this reason that most times these stem winder hand brakes are almost never applied, even today, better to chunk the wheels than apply this miserable type hand brake. OK enough of that.

    I think the brake pipe boss you have is great. works for me.

    I would rather use a screw to mount the coupler box and file if needed, gluing these type of serviceable options has presented issues for me in the past. Pilot hole please.

    Train line and jacking pads. Lets me think out-loud a bit. Can you make this part with a relief to accommodate the train line? Actually we may need a separate sprue for the jacking pads, the brake wheels that come with the Tichy is not period correct, and other details we haven't discovered yet.

    The Plano cut bar hangars I have too, just not sure which cut bar was actually used.

    Gonna show my ignorance again. What is a NBW casting? Are we talking about a Brass type printing or other? Just curious. May need to use some of that Tungsten putty if needed. Just want to understand what your method is. I am like a cave man seeing the space shuttle land or take-off here.

    But I am really impressed, nothing like seeing this actually happen. I may need to take a few courses now. I cant thank you enough, really impressive.
     
  3. RailMix

    RailMix TrainBoard Member

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    Looks good, guys. Good to discuss which details should print and which won't. (Yeah, I remember laboriously applying rivets to a steam locomotive cab and then having to go back and make them slightly oversize so they would print.)

    BTW, very nice job on the CAD work. Which software are you using?
     
  4. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    I haven’t touched anything today, but I will show you what I’m going for. I can get rid of the lower bracket entirely or move it onto the end sill to be horizontal. The photo shows what I am trying to model: one on the side, and one underneath the car. The reflections on the brass make it kind of hard to see exactly what the brackets look like, which alongside with printing limitations, are why mine are simplified. You could treat the lower as a mounting pad for the Tichy winder or I can move it or delete it. I will leave the air hose mount as is. If you have the Plano cut bar hanger, I can leave mine how it is, or I can remove it as well. If you want to keep it, we can see how it prints and file if off as needed.
    The brass car has a simple cut bar, no trombone style or any kind of slider, so if you want to follow this model, here is your answer as to what kind of cut bar it has.

    NBW- nut bolt washer casting- you can see the bolt detail below the grabs on the brass car. It probably won’t look good on the print, so I was just saying to buy Tichy injection plastic ones and glue them on. Those are really optional, my current Green Diamond project is the first time that I have personally used them.

    I will try to remove the jacking pads and make them separate parts. That way, the brake air hose can be installed under them.

    What kind of stirrup are you going to use? The stirrup on the brass car has a second step on it since the side sill is recessed. (Left) The other side of the car is flush, so there is only the one step. (Right) That one could be A-Line, while the other one might have to be printed, unless there is a plastic one out there.

    Railmix- the software I am using is Autodesk Inventor.

    C1AD494C-DDE7-4CBC-A757-709479CF4AF9.png
     
  5. gjslsffan

    gjslsffan Staff Member

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    OK. Good to take break.
    Honestly. I think you can leave the lower hand brake boss, as you designed, and I can remove it if needed. Better to have it and not need it, than need it and not have it right?

    Also lets see how the cut lever hanger prints, again easily removed if needed.

    Can we print both sides of the stirrup steps and again remove if desired? A-line is my first choice. The other side (double step) could be a passenger car part too. But I don't think I know where to find any.

    The cut bar they show is kinda weak IMHO, I think we/I can do better.

    I can work around the jacking pad issue as well just bend and glue to fit.

    Trying to find a brake wheel to work on this. These stem winders had a smaller brake wheel, but not the spiral design that Tichy uses.

    You have done so much with so little, that you are now qualified to do anything with nothing.
     
    Last edited: Jun 27, 2019
  6. wvgca

    wvgca TrainBoard Member

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    I can try printing the resultant stl file on a regular PLA printer, [rather than a Photon,, which I don't have] but I know the cut lever [and other fine details] will not print properly ..
    But the main part should come out okay ..
    It will be printed as an exercise only, it doesn't work on a 1890's layout .. :)
     
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  7. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    I went and made a sprue for the two jacking pads on one side so you can glue the air line underneath them. Here is what I intended the brake line to look like. It should run under the top deck, from a hole in the side to another on the end block. Here is a rough sketch: The side/top views aren’t to scale, and in fact, they don’t even match the picture, but you get the idea. The notch on the jack pads then line up with the air hose. image.jpg
    I also went and made the corner stirrups. They look a little chunky, so I hope that they have a chance at printing. I tried to get a photo angle that showed the asymmetrical steps and how they look different. The photo is upside down, but that is the benefit of an isometric view; it makes sense from any angle. One thing I still need to make is the screw hole for the coupler box. Do you want it flush with the edge of the anticlimber or with the end sill? Any other position? I just want to know where the screw hole should be located. The last major part I need are the bolsters. I need the height of the TSP truck and how far off-center the mounting screw is to set the correct ride height and truck centers. If the TSP trucks don’t work, I can try to make a 3D printable truck for those 30” wheels. That is a scary prospect, since they are a functional part and need to actually work well, not just look realistic. 69DDD1FE-CE9C-4AEF-96DC-F5EA77C3CFD7.jpeg
     
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  8. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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  9. gjslsffan

    gjslsffan Staff Member

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    I am hoping to get the the TSP trucks in a couple days, and the wheels a day or two after that so I can get you the measurements you need.
    I think the coupler box (#58) will go at the end of the anti climber. the center of the screw mount hole is .250 from the front of the coupler box, the overall width of the coupler box is .262 and .472 over all length of the coupler box. I chose this draft gear as it is among the narrowest, to aid in the swing of the trucks. Looks like a #90 screw to mount the coupler.
    I would like to see what you come up with for designing a truck. Is the material flexible enough to put in the metal axles? I have a concern with the TSP truck not having enough clearance on the bottom.
    Will see in a few days.
     
    Last edited: Jun 28, 2019
  10. gjslsffan

    gjslsffan Staff Member

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  11. gjslsffan

    gjslsffan Staff Member

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  12. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    What is the diameter of the 0-48 coupler mounting screw in inches? That is the screw in the diagram on the Kadee website that you attached. I want to make sure that the hole is slightly smaller so it can be tapped.
     
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  13. gjslsffan

    gjslsffan Staff Member

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    OK will do, will be home in a couple hours.
     
  14. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    I also designed sideframes if you want them. I have no guarantees that they work well. The axle bearing cone spacing between the two sideframes is about 1.5 scale inches wider than the 1.015” NWSL axles and a little larger in diameter, so in theory they should fit, but after it prints I don’t know how smooth everything will be. They are designed to screw onto the bolster like the Walthers passenger trucks do. That way you can get the axles in without having to flex the sideframes and possibly snap whatever material it is 3D printed in. (Another upside down photo) image.jpg The bolster has one centered hole and another one offset 24 scale inches. I added a dimple on the bottom of the car that corresponds to that hole. If you want to use it, you could drill it out. Otherwise, the top of the car only has the original pilot holes for the coupler and the centered truck screw. The new offset hole is only partial depth.
     
  15. gjslsffan

    gjslsffan Staff Member

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    That looks sooo much better than my attempt, was/am not happy with the result, could not put the springs where I wanted to. I dont have any Walthers 3 axle trucks but I can get some. Can you shoot me a part# for the walthers truck these side frames will fit plz? I dont know if all Walthers 3 axle bolsters are the same.

    The screw I am gonna use to mount the coupler box is a 00-80 it is .052" threads OD, these 00-80 screws are a slip fit, any thing larger would require drilling.

    Thank You!
     
    Last edited: Jul 1, 2019
  16. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    I just meant that I used the Walthers techniques to design these trucks. You don’t need to buy any. I have both parts right here. What screw are you going to use for the truck kingpin screw? I intended for the screws that hold the sideframes to the bolster to be 2-56, but would you use the same type to hold the bolster to the car? If so, I am going to make the holes smaller.

    Bolster:
    image.jpg
    Truck photo that isn’t upside down: image.jpg
    Here is a photo of the bottom of the car. The middle of the three holes is the original center mount, while the other two are for mounting using the offset hole on the truck bolster. You can choose whether you want the truck to rotate closer to the coupler or to the center of the car: image.jpg
     
  17. gjslsffan

    gjslsffan Staff Member

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    OK thanks for clearing that up.

    Yes I think its a good idea to make the truck mount screws to be 2-56 just like truck assembly screws.
     
  18. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    Do you still want the option of using the TSP truck? I can take off that block on top of the bolster and extend the center sill on the car to compensate. The thicker center sill is more prototypical, but rules out the TSP truck as a fall-back option if the 3D printed ones don’t work. I can revert it if you want me to. Other than that, is there anything else on the car I would need to make? I think we are getting close to finishing the design work.

    Modified bolster: image.jpg
     
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  19. gjslsffan

    gjslsffan Staff Member

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    HHMM, I think that TSP truck that I worked on is out LOL. It is no where close to your design, no reason to think yours wont work. The TSP trucks have too much end play as well.
    A question. Can you make the space between cones .5 inch? I have a turning tool to make the truck journals more contour to the axle ends. Just a thought. What do you think? I have no experience with 3D printed stuff. Are they able to print the bearing surface that accurate?

    I think this is just great!
     
  20. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    The carbody would probably have to be done on a larger printer, which is probably coarser. The trucks could be done on a smaller and more precise printer and it may be possible. I have seen some extremely accurate printers, but I don’t know what exact devices Shapeways or others have. If I do make the bearing width narrower, your Truck Tuner (the tool I assume you are talking about) could probably ream it deeper if it prints too narrow. The bolster is pretty easy to duplicate out of styrene if you need to widen the space between the sideframes as well.
     
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