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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    Thanks Echidna,
    My intention has always been to just run the rail cars individually or as they are, certainly in the case of the express parcels.
    The passenger rail car could have a coach or a couple of vans as you say, just to create a bit more interest.
    The running trials I`m conducting at the moment are designed to stress the new replacement gear, and indeed try and break it, because we are in unknown territory here.
    Can a 3D print of this small size stand up to the everyday punishment required of it in the rail car gear train...???...who knows...???....but for my own peace of mind and probably Chris`s as well....I need to know.
    The results will help anyone going down this route in the future hopefully
    So at the moment....the big question....and probably the only question is .....will it last ?....because we now know that it certainly works.
    Happy days Echidna, when we can source new parts from 3D printers and keep the trains running.....:thumbs:
    :tophat:Gormo
     
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  2. Mossy

    Mossy A classic grump Yorkshire man Full Member

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    Gents

    Having spent the last 18 months playing with 3d printing it seems to me the perfect role for it along with replacing mis-shaped castings and odd things like brake shoes to eliminate shorts etc. As a couple of examples Rob wanted replacement brake shoes for his mega Princess build so he could get them prototypically tight up to the wheels a simple print job once he sent me the .stl file, I have also printed shoes for a couple of other loco builds he has in mind, and am awaiting his redrawn Princess firebox for similar treatment.
    The newer stronger or more resilient resins will probably increase the application of this technology.

    Have a good Christmas down there in oz, I assume you aren't expecting snow.
     
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  3. gormo

    gormo Staff Member Administrator

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    Thanks Mossy.......Merry Christmas to you lot up North too.
    We won`t get snow here but so far we`re having a cooler than normal lead up to the festive season.....things are a changin`
    :tophat:Gormo
     
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  4. gormo

    gormo Staff Member Administrator

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    Further running on the rail car today, approx. 30 minutes with a train in tow and a further 40 mins running the length of the branch and back under the control of the auto shuttle.
    Still no issues........:thumbs:
    :tophat:Gormo
     
  5. Vinylelpea

    Vinylelpea Full Member

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    May the 3d printing gods be with us, we expect nothing less. :giggle:
     
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  6. Andy_Sollis

    Andy_Sollis Staff Member Moderator

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    No Chris, I wasn't referring to the FDM print re Nylon, more the SLS or multi jet fusion prints done at industrial level.

    As you say, I doubt we could get an FDM printer even with a .2 nozzle to print a good enough rendition. If only we had this 20 years ago - the number of scalextric car gears I used to swap as the nylon motor gear had split and just spun the motor and not the axle... :scratchchin:

    You may be on to something here ! :hammer:
     
  7. Andy_Sollis

    Andy_Sollis Staff Member Moderator

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    Cracking Gormo ! I love the track circuit diagram! I take it I missed the bit where you wrote that up? (may even be before I joined)
     
  8. gormo

    gormo Staff Member Administrator

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    Thanks Andy,
    I think you`re talking about my train detection system track diagrams.
    That is explained in the video below from 15 mins 22 secs starting point.
    I have since changed the method of detection, however the panels still work in the same way


    :tophat:Gormo
     
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  9. Andy_Sollis

    Andy_Sollis Staff Member Moderator

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    Really good Gormo ! I like that!

    I'm now wondering if I can replicate that in some way to show the outside sections on dads outdoor line, but I bet I would need to be keeping it clean/polished to work. And I suspect four lour line would cost dad a small fortune in cable :facepalm:

    very neat.. Impressed. How did the diodes work out with the delay ?

    Andy
     
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  10. paul_l

    paul_l Staff Member Administrator

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    Block dectection, it's actually easier with DCC than DC.
    If you're a member of MERG, take a look at their current detection modules, the output of the module is fed into a CBUS input module, the modules(s) are connected (daisey chained) to each other and the command station and/or usb computer interface via a 4 wire cable (+12V, 0V, CANH & CANL).
    In the simplest form each module sends it current condition the the input modules(s). Once the condition changes, a event message is sent along the bus. Other modules listen to the bus, if an event they are looking for occurs they will carry out the action they are programmed to do - switch on an Panel LED, change a signal, close a level crossing etc,etc.
    Multiple modules can respond to a single event, allowing multiple mimic panels to show the current status of the track occupancy.

    The Dark side awaits .............

    Paul
     
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  11. Andy_Sollis

    Andy_Sollis Staff Member Moderator

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    :scratchchin:

    I feel another Auduino project coming on ! :giggle:
    I'm not a member but I work with a chap who is !
     
    Last edited: Dec 23, 2022
  12. gormo

    gormo Staff Member Administrator

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    Well folks,
    It`s time to evaluate the 3D printed gear.
    I`ve removed it from the loco today after it`s had considerable running, enough running indeed to break it if that was going to happen, and in fact it is not going to happen because the integrity of thing overall is good.
    I think however, the one thing to be considered is the product used for lubrication.
    What you will see in the video below is some pitting on the surface of the gear which I think must be due to some incompatibility with Inox.
    Inox is supposedly safe on most plastics, but I think long term on resin it may slowly eat it away.
    Therefore, the search is on for a non corrosive, non toxic method of lubrication.......my first thoughts being a vegetable oil or some such thing which you would think would be safe enough to use.
    More research required on that one.
    Anyhow......I think the 3D printed gears are up to the job long term, but we don`t know these things until we try them, so I am always open to trying things, because eventually most problems can be solved.
    This image below shows what appears to be a surface that is eroding and that must be down to the lubricant.

    PICA0021.jpg



    A video through the microscope



    :tophat:Gormo
     
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  13. Chris M

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

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    Hey Gormo,

    The pitting is interesting but as you say does not appear to be significant. Inox might be the cause. As an alternative what about graphite powder? I don't recall anyone ever talking about using graphite to lubricate model train gears but why not ... it is very slippery and should stick to the gears. It certainly works well on locks.

    Chris
     
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  14. gormo

    gormo Staff Member Administrator

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    G`day Chris,
    Yes I`m not particularly worried at this stage about the pitting, however what is unknown is it`s effects long term. The Inox may be working away like a cancer that will slowly destroy the part.
    I have wiped the part and surrounding gears clean for the moment which might slow the process ......so we wait and see.
    In the meantime....I`m open to ideas like your Graphite suggestion.
    I think some people use it on their track to improve electrical conductivity ??....but I think I remember reading that process plays havoc with traction tyres.....not sure....can`t remember....:faint:
    Anyhow I will try your suggestion when we emerge from the Christmas excess and dull hangovers......Oh just remembered..... gotta get through New Years yet.....:facepalm:.
    I will research again on the internet and there is bound to be a simple solution that has been flying under the radar all this time.
    Ain`t technology great....:thumbs::thumbs::thumbs::thumbs:
    :tophat:Gormo
     
  15. Vinylelpea

    Vinylelpea Full Member

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    Maybe no lubricant required. I was told by an engineer, that you should never lubricant nylon gears. However I use a food grade gease I bought on ebay, from memory it was $15 including postage. Apparently Inox is not good for traction tyres.
     
    Last edited: Dec 26, 2022
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  16. Andy_Sollis

    Andy_Sollis Staff Member Moderator

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    The graphite lubricant was for many years used in Speedo cables to allow the coil to turn freely.
    We are of course talking metal there though, so again it comes back to long term effects.

    great to know strength wise it’s fit for purpose. :thumbs:
     
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  17. Walkingthedog

    Walkingthedog Full Member

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    One problem with lubricating non metal gears is that any dust/dirt that sticks to the lubricant may wear out the gear.
     
    Last edited: Dec 26, 2022
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  18. gormo

    gormo Staff Member Administrator

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    :scratchchin:
    :tophat:Gormo
     
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  19. gormo

    gormo Staff Member Administrator

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    I guess one solution for lubrication could be KY Jelly........a tip that was passed on to me years ago.
    Safe to use on human skin and I think it`s water based..???
    Just looked it up.......contents are .....Water, Propylene Glycol, Hydroxyethylcellulose, Benzoic Acid, Carbomer, Sodium Hydroxide.......Hmmmm...?????
    :tophat:Gormo
     
  20. Andy_Sollis

    Andy_Sollis Staff Member Moderator

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    I know Vaseline is used on gaskets on cars!
    No idea what it really is, but for some reason when I read Propylene Glycol I think Aircraft? :scratchchin:
     

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