3D Printed Lima Gear Replacement

Discussion in 'Workshop Benches' started by gormo, Dec 19, 2022.

  1. gormo

    gormo Staff Member Administrator

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    I believe Vaseline is a petroleum based product Andy and therefore would be unsuitable........probably would do more harm than good.
    :tophat:Gormo
     
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  2. Sol

    Sol Full Member

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    I have used sparingly LGB Gear lubricant 51020
     
  3. paul_l

    paul_l Staff Member Administrator

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    A quick seach on t'internet , and PTFE seems to be the recommended solution. Both WD-40 and 3in1 offer solutions, the WD-40 Specialist Anti Friction Dry PTFE (I have a can ;)) works fine so far.

    Paul
     
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  4. gormo

    gormo Staff Member Administrator

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    G`day Folks,
    Today I added some of my new couplings to the Lima Parcels that had the replacement gear added.
    I had to open it up to remove the old D tension locks and a quick survey of the 3D printed gear showed that it was still intact and seemed quite OK.
    Nothing to comment on really.....:scratchchin:
    This is how it looks now with the new couplings.....visually a great improvement over the old tension locks

    IMG20230308145250.jpg



    IMG20230308145302.jpg



    IMG20230308145317.jpg

    And underneath showing the coupling fitted to the bogie.
    There is a hole drilled through the base of the bogie to anchor the wire for the coupling. It is initially held in place with some Super Glue and then adjustments are made and finally the wire is permanently anchored with UV Glue.

    IMG20230308145339.jpg

    :tophat:Gormo
     
  5. Gary

    Gary Wants more time for modelling.... Staff Member Administrator

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    Nice work Gormo. :thumbs:

    I'm guessing that you had to bogie mount the new coupling as there is too much body yaw on the curved track and through points ?

    Cheers, Gary.
     
  6. gormo

    gormo Staff Member Administrator

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    Yes exactly right Gary,
    Basically any vehicle with bogies....ie. diesels, coaches or freight wagons and not forgetting some steam locos ( no bogies but pony trucks ) with have some degree of swing or body yaw as you call it.
    In a nutshell, the length of the body is proportional to the amount of swing you get at the ends of the vehicle.....so it requires some testing to work out the limits of the couplings and if the limits are exceeded, we need to mount onto the bogies rather than the buffer beam.
    :tophat:Gormo
     
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  7. Vinylelpea

    Vinylelpea Full Member

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    Same with my Bachmann 03 shunter. Gets run every day and 3d printed gear working great. Glad to hear you're having same success[/QUOTE]

     
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  8. gormo

    gormo Staff Member Administrator

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  9. paul_l

    paul_l Staff Member Administrator

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    And sounds relatively quiet - well for a Lima :avatar:

    Those camera angles were really effective, especially comming into Little Barford

    Paul
     
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  10. Jim Freight

    Jim Freight Full Member

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    I'm just getting into 3D printing with filament, I'm just curious whether a gear like that could be printed in nylon filament using a 0.25mm nozzle, although as I understand it nylon often needs to be dried before use as it is rather hygroscopic, and can block nozzles easier than other materials e.g. ABS or PLA, and of course using a small diameter nozzle makes that even more likely.

    I have also been looking at whether to get a small resin printer for such things, but it seems so messy and needs better ventilation than filament based printing, not making it very good for use in a domestic environment. It seems akin to the days of developing and print roll film from cameras my dad used to do before the convenience of digital cameras revolutionised picture taking (I deliberately avoid the term photography) arrived.

    Typically I would only need a small resin printer for gears, bushes etc, but many printers are quite large, it seems to be yet another minefield to tip toe through :avatar:

    Jim
     
    Last edited: Mar 17, 2023
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  11. Vinylelpea

    Vinylelpea Full Member

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    Resin printers are smelly and can be messy. Also not great for environment. Tread carefully. But with care can be used safely.
     
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  12. Chris M

    Chris M If 2 wrongs don't make it right ... try 3 Full Member

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    The gear I made for Gormo was printed with water based resin and is still working well on his Lima loco. When I bought my resin printer I also was not looking forward to using normal resins because of smell and handling issues. So I decided to try water based resin.

    So far the results have been good EXCEPT for the buffer stops I gave Gormo which buckled and flaked when soaked with glue diluted with water when he added scenic grass around them. See Gormo's detailed video about this issue. It was solved by painting the buffer stops with enamel paint before weathering.

    I haven't tried nylon resin and it may be superior BUT so far the water based resin is doing well for everything I have used it for. Water based resin gears should not be a problem because they will only ever be soaked in oil. I have normal resin but I am still using up my water based stock and because it is so easy to work with I am not in a hurry to change to the messy/smelly resin ... but I will eventually.

    Hope this helps ... Chris
     
  13. Jim Freight

    Jim Freight Full Member

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    Thanks Chris.

    That seems to infer that the water based resin parts may not be water resistant in the long term for any nylon parts used where water may be present either.

    So would painting with acrylic paints also be an issue?

    These days for painting models I have moved over to using acrylics, less mess and fumes, even though acrylics seem to destroy brushes, whether sable or synthetic, and to get them to adhere to plastics and metals I find a spray coat of acrylic primer is nearly always required.

    It would almost be ironic if I have to use an oil based paint to seal a water based resin print before painting with acrylic paints. :scratchchin:

    Jim
     
  14. Chris M

    Chris M If 2 wrongs don't make it right ... try 3 Full Member

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    Yes Jim, I see your point.

    I did some testing after Gormo found the water based buffer stops distorted. It took a buffer stop over a day sitting in water for the resin to distort and flake. So water would only be an issue if continually present, an odd brief wetting should not be an issue (I hope). I guess the bottom line would be if there is any chance than a part can get wet don't use water based resin.

    Enamel paint definitely works. However, Gormo did paint the parts with acrylic paint and they still distorted BUT the bases of the buffer stops were not painted. All distortion occurred at the base which was sitting in wet glue and water until fully dried. The one thing we didn't test (I think) was ... would any distortion occur if the model was completely painted with acrylic paint?

    Even though acrylic paint is water based I think it is waterproof when dry (or at least water resistant) so it should work. Worth a try I think ... I will check this myself when I get a chance.

    Chris
     
  15. Jim Freight

    Jim Freight Full Member

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    As I understand it that when acrylic paint first starts to dry, and it is touch dry seemingly in seconds, it can be cleaned off with water so it must still be 'wet' as such.

    But after it is left to cure for 24 hours it does not wash off easily with water, so presumably it is just the period prior to (the paint) curing is crucial.

    Admittedly when I am laying ballast and grass it does get very wet, especially when I use a fine water sprayer during the process, after which it can take a few days for everything to dry out properly afterwards, I think this is particularly the case when using the crushed nut shell type ballast e.g. Woodland Scenics, which absorbs water, instead of laying granite ballast.

    Jim
     
    Last edited: Mar 20, 2023

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