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A 3D printing virgin

Discussion in 'Workshop Benches' started by Mossy, Aug 8, 2021.

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  1. Sep 1, 2021 #101
    Rob Pulham

    Rob Pulham Happily making models Staff Member Administrator Feature Contributor

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    Zoom or Skype works for me.
     
  2. Sep 1, 2021 #102
    Andy_Sollis

    Andy_Sollis Staff Member Moderator

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    Think I just did circles and chopped them in half, then shortened them to each length. A7CE7F91-1172-4EC4-AF4D-01EF89F2B167.png
     
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  3. Sep 2, 2021 #103
    paul_l

    paul_l Staff Member Administrator

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    Those springs are mighty impressive

    OK gents I think I have some scanning to do.

    I have "Railway Mechanical Engineering Vol 1 & 2" Published in 1923 by the Gresham Publishing Company.

    Vol 1 has sections covering

    • Materials used in Locomotive construction
    • Carriage and Wagon design
    • Carriage lighting
    Vol 2 has sections covering

    • Locomotive Workshop practices
    • Maintenance
    • Electric Traction
    In Chapter 6 Springs and Ironwork (part of the Carriage and Wagon desin section), we have 7 pages of explanation, drawings and calculations for the design of leaf springs, even covering the buckles.

    In the wheel section we have the design of a PO wagon wheel and axle for 8 & 10 Ton wagons (8 plain spoke) and 20 Ton PO wagon wheel and axle (8 open spoke)

    I love the comment regarding Axle Oil - "The oil used for lubrication varies much in quality, as will be seen in the price paid by the different Companies ranges from 6d to 5s 6d per gallon (pre war prices)"

    This may be a long read, and lots of drawings as well.

    Paul
     
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  4. Sep 6, 2021 #104
    Mossy

    Mossy A classic grump Yorkshire man Full Member

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    Paul,

    Loved your sprung horn block idea, so I have copied (plagiarised it), I hope you don't mind. Can't print it as still waiting for replacement FEP plate so it's like yours at the experimental stage.

    Also been playing trying to draw a buffer and housing.

    The housing looks pretty good, first time using the revolve function so another cherry popped.

    2021-09-06 (1).png

    Then got really bold and decided to play with a buffer head. First go it was just an extruded circle which looked %$^%%$, so tried using the loft function (ano cherry to pop), but whatever I seem to do rather than coming out as a gentle convex dome it's distinctly concave. Anyone got any ideas what I am doing wrong?

    2021-09-06 (2).png

    Keep well guys

    Mossy
     
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  5. Sep 6, 2021 #105
    Mossy

    Mossy A classic grump Yorkshire man Full Member

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    Solved the buffer head problem - when you think about it its obvious as she who must would say just another senior moment.

    2021-09-06 (3).png
     
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  6. Sep 6, 2021 #106
    Andy_Sollis

    Andy_Sollis Staff Member Moderator

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    Looks good! But also looks fine. You may need to add a touch of beef for strength in these small scales. Remember we’re resin not turned brass. Sometimes we have to compromise.
    andy
     
  7. Sep 6, 2021 #107
    Mossy

    Mossy A classic grump Yorkshire man Full Member

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    Hi Andy,

    I have 2 versions of the buffer, one with a resin shank the second the shank is bored out to take .9mm wire to add greater strength.
    I'm going to print both and play around, but more that likely will end up using the strengthened version.

    Mossy
     
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  8. Sep 6, 2021 #108
    Andy_Sollis

    Andy_Sollis Staff Member Moderator

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    I was thinking more the head than the shank. I’d add another .25mm behind it if not .5mm… just going from experience.

    andy
     
  9. Sep 7, 2021 #109
    Mossy

    Mossy A classic grump Yorkshire man Full Member

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    Andy,

    Thanks for the comments. I will create 2 new models with .25mm and .5mm backing respectively and then print all three.
    I can then judge which is best,

    Mossy
     
    Last edited: Sep 7, 2021
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  10. Sep 7, 2021 #110
    Andy_Sollis

    Andy_Sollis Staff Member Moderator

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    An excellent idea..
    Although I’d like you to prove me wrong! I may have been over doing things, but it’s surprising how brittle some parts can be… you could also put a small bead on the inside to increase the surface area from the shaft to the back of the buffer head.
     
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  11. Sep 7, 2021 #111
    Mossy

    Mossy A classic grump Yorkshire man Full Member

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    As per your suggestions.
    This one has a .25mm backing and an extra .5 reinforcement.
    I have also modified the .5mm backing model to have a similar reinforcement.
    Both are "drilled out" to take .9mm rod as a reinforcement for the shaft.
    I have deleted the resin only example.

    2021-09-07.png
     
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  12. Sep 7, 2021 #112
    paul_l

    paul_l Staff Member Administrator

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    Hi Mossy

    Can I suggest putting a fillet between your reinforcement and the buffer head. When printing you will go from a small diameter to a vey large diameter in one layer change. The fillet will give a transition, and allow additional supports to be established before the large surface is printed.
    Also suggest printing these like mushrooms, with medium supports around the thinner edge and heavy supports in the thicker mid portion.
    If youre feeling adventurous, why not apply a screw thread to the end section.

    Paul
     
  13. Sep 7, 2021 #113
    paul_l

    paul_l Staff Member Administrator

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    Also found this video on spliting models that are too large to print.



    Paul
     
  14. Sep 7, 2021 #114
    Mossy

    Mossy A classic grump Yorkshire man Full Member

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    Paul

    I don't need a screw thread I am using Jim McGeown's springing system. Piano wire through end caps like these and also through the coupling hook.
    I used his system on the 4 wheel saloon and it worked very well so I am trialling it in resin. It may or may not work but nothing is lost by trying it.
    It also saves buying commercially available buffer heads and springs etc.

    I will also create a new buffer with the reinforcement as a fillet not a collar.

    A question. IS there a lettering option in Fusion, I am drawing a Mineral buffer for the V1/2 and the buffer has an integrated step with treads and NER lettering.
    I have tried hand drawing the letters but arghhhhh!!!!!!!!!!! it's horrible.
     

    Attached Files:

  15. Sep 7, 2021 #115
    paul_l

    paul_l Staff Member Administrator

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    I can't find it either, which is very disapointing as I can do it in 123D - Andy stop smirking it's very un-professional :avatar:

    Paul
     
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  16. Sep 7, 2021 #116
    Andy_Sollis

    Andy_Sollis Staff Member Moderator

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    Moi?

    :scratchchin::avatar:

    There must be one.. I’m sure I’ve seen someone put text on a model? And it was easier to lay out than on 123d, as you could curve it..

    i will have a look later..
     
  17. Sep 7, 2021 #117
    Andy_Sollis

    Andy_Sollis Staff Member Moderator

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    I’ve hit a wall with the MTV.. I’ll post a bit here and update the main thread later…

    so, I’ve come to my axle boxes. I’ve copied the metal wheelset as best I can on 123d and it fits grand in the chamfered bearing hole in the back of the axle box on the model with plenty of space to spare..

    but, come to fit the real wheels in the same parts on the printed model and the axle boxes point outwards….

    now I’ve either got a measurement totally wrong somewhere or….. do I need to drill out the (no idea what the correct term is) cone where the pin points sit behind the axle boxes so they sit further in? (I’m not using bearing cups)

    how have you guys found tolerances?
     
  18. Sep 7, 2021 #118
    Andy_Sollis

    Andy_Sollis Staff Member Moderator

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    does this help??
     
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  19. Sep 7, 2021 #119
    Mossy

    Mossy A classic grump Yorkshire man Full Member

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    Andy,

    Thanks for the link. I needs to sit, listen and learn now.

    Replacement FEP's arrived this morning so one has been installed and a print test set running.

    Mossy
     
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  20. Sep 7, 2021 #120
    Mossy

    Mossy A classic grump Yorkshire man Full Member

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    Well it works:

    2021-09-07 (2).png
     
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