Window Transmission Gears 3D Printing

Discussion in 'E9 Projects & Restorations' started by TravL350, Mar 10, 2017.

  1. Markos

    Markos Parts Hoarder Site Donor $

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    The metal/bronze stuff is like pot metal so I wouldn't keep your hopes up. I think the nylon will do fine. One question though, would it be stronger if the ridges for the metal cog were in the valleys of the plastic gear? You would maintain an overall thickness around the plastic ring. I'm not sure, but curious.

    I've been thinking about using ULTEM for the relay bases. It is propane torch resilient!

    http://www.stratasys.com/materials/fdm/ultem-9085

     
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  2. TravL350

    TravL350 Member Site Donor

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    Hi Mo - I got a quote for machining a delrin gear, as well as a PTFE (Teflon) and it was going to be about $150 do CNC any plastic, so probably cost prohibitive considering you can occasionally find the whole gearbox for less than $50. Also, like Steve said, I am not sure a plastic cored gear would hold on to the spindle for very long before stripping.
     
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  3. TravL350

    TravL350 Member Site Donor

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    Yes I think that would make it a bit stronger! I'm less worried about failure in that area though, because I think either one of the sets of teeth will give out first
     
  4. Stevehose

    Stevehose Well-Known Member Site Donor $

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    Looks like you could just make an open sided gear with the inner teeth to match the metal teeth and slip it onto the metal gear then bond it with some nasty adhesive?
     
  5. TravL350

    TravL350 Member Site Donor

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    Yes, I think so Steve - hopefully with this design we won't even need an adhesive. The Nylon will expand a bit as it soaks in grease which should make the press fit even tighter
     
  6. m73

    m73 Member

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    That's a lot of $$ for such a part! How about re-sleeving the striped outer edge only?

    I would round the perimeter, then re-make the gear portion + a center portion w/recess to fit on-top on the metal area. That way you have max adhesion surface area. Maybe even make the center recess on both sides if space willing.

    Of course you are much closer to a solution than this....just thinking outside the box.

    Best of luck,

    -M
     
  7. TravL350

    TravL350 Member Site Donor

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    I just received a NOS transmission I bought from eBay and discovered it's gearing is 38:1 instead of 48:1 like my car has.

    BMW part no. on the box is 51371801878 - same as the 48:1 as far as I can tell.

    Bosch P/N is:
    0 142 800 004 for the 48:1
    3 136 201 001 for the 38:1

    Anyone know the history on this?

    Travis
     
  8. rsporsche

    rsporsche Well-Known Member Site Donor $$

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    i will be opening a gearbox from a 70 2800cs in the next day or so. i will count.
     
  9. Stevehose

    Stevehose Well-Known Member Site Donor $

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    often the ratio is printed under the part number
     
  10. TravL350

    TravL350 Member Site Donor

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    Got parts today!
    Here is the nylon 12 gear:[​IMG][​IMG]

    With the existing metal core pressed in:
    [​IMG][​IMG]

    And here is the SS/Bronze part:
    [​IMG]
    [​IMG]

    The metal one came out far better than I expected! It seems very strong and dense. Not sure how noisy it will be though.
    I'll put these both in my car this weekend and compare functionality / noise between the two new parts
     
  11. TravL350

    TravL350 Member Site Donor

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    Here is the Nylon version in place inside the transmission [​IMG]
     
  12. rsporsche

    rsporsche Well-Known Member Site Donor $$

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    looking forward to hearing how the 2 different products work. i'm not in need right now ... but sooner or later a bunch of us will.
     
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  13. Markos

    Markos Parts Hoarder Site Donor $

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    Fantastic job! Does the stainless/bronze one have splines on it?
     
  14. TravL350

    TravL350 Member Site Donor

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    Thanks Markos! I didn't include splines in the metal part because I had to "under-size" the hole to allow for shrinkage. I'm planning to drill out the hole a bit, then press it on to the splined shaft. However, the material is very hard. I was expecting it to be softer & more workable because of the bronze infiltration, but it seems much more like steel. So, I'm not sure if I'll be able to successfully press it on to the splined shaft.
     
  15. TravL350

    TravL350 Member Site Donor

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    I managed to drive the splined shaft into the gear (took some serious pounding) to "cut" the splines into the hole. Next time I'll make the hole in the 3D part 0.5mm larger diameter so I won't have to drill it out

    [​IMG]
     
  16. Markos

    Markos Parts Hoarder Site Donor $

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    Hmm this stuff seems stronger than what I have been told. I wanted to print CSI airbox brackets but I figured it wasn't strong enough.
     
  17. adawil2002

    adawil2002 Well-Known Member Site Donor $$

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    Those look excellent.
     
  18. TravL350

    TravL350 Member Site Donor

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    Yeah, I am pretty impressed by the material. The finish is rough but it's way stronger than any plastic 3D print I've ever seen.
     

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