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Designing a chain case

  1. Jul 14, 2006 #1

    wolram

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    The rebuild of my bike is well under way but i have hit a snag, i decided to convert the primary drive from chain to belt drive, all the parts are under construction, the problem is the origonal housing is 3/8 to narrow, and these
    housings are notorious for leaking oil any way, the oil comes from seepage
    past the main bearing, the origonal housings are held together with a band.

    So i need to make some thing to fit the bill, obviously i want it to look good,
    i was thinking of using a welded s/steel construction, with the (back plate)
    just made out of say 2mm flat sheet, it is the (cover) that is the biggest problem, how the heck do i get it to look good, as if it were made for the bike and not just an after thought?
     
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  3. Jul 14, 2006 #2

    FredGarvin

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    A few of thoughts:

    1) If you made it out of aluminum in stead of stainless, after all the machining, etc...you could have the final product anodized. This will give you a very wear resistant surface, a slight increase in mechanical properties and you can anodize a lot of different colors. It's not very expensive also.

    2) If you stick with stainless, you could give it to a machinist to either polish it or put repetative tooling marks on it, similar to what you see on the cowling of the Spirit of St. Louis: http://www.atpm.com/7.01/washington-dc/images/spirit-of-st-louis.jpg

    3) Powder coat or black oxide the cover.
     
  4. Jul 14, 2006 #3

    Q_Goest

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    Can you post some pictures of the area your modifying?
     
  5. Jul 14, 2006 #4

    wolram

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    Last edited: Jul 14, 2006
  6. Jul 14, 2006 #5

    Q_Goest

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    Nice ride. I built my own bike about 25 years ago. Rode it for about 10 years, then mothballed and finally gave it away <sigh>

    When you say "primary drive" are you refering to the chain between the crank and tranny or the rear wheel and transmission sprocket? I assume it's the former? If it is, doesn't that push the other chains outward?

    Regardless, I have to believe you're interested in keeping the original look, so you'd want to duplicate that black finish as close as possible. What details are you concerned about?
     
  7. Jul 14, 2006 #6

    wolram

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    That is not my bike by the way but i hope mine will look as good when finished..

    Yes it is the casing that encloses the drive from engine to clutch, the dynamo is also belt driven and is an easy fix to move out 3/8in, the drive from clutch to back wheel will be as origonal

    My main concern is that every thing must (blend in), as i can not recreate the curves need for the band type clamping that holds the two halves of the cases together, nor would i want to as it is almost imposible to seal them, a well known problem of the Velo.
     
    Last edited: Jul 14, 2006
  8. Jul 14, 2006 #7

    Q_Goest

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    How about milling the cover from a block of aluminum, then painting or powder coating? Do you have access to a machine shop? By milling, you could eliminate welds and get some nice rounded corners too. Probably would seal a whole lot better as well.
     
  9. Jul 14, 2006 #8

    wolram

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    I do have accsess to a mill but only very limited tooling, i could not machine
    the curves :grumpy:
     
  10. Jul 14, 2006 #9

    Danger

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    Good pix, Woolie. You've lost a bit of weight and 50 or 60 years since your last photo.
    The example that Fred mentioned, as in the Spirit of St. Louis, is commonly referred to in the street scene as 'engine turned'. It's used a lot for dashboards on street rods, usually in aluminum.
    I don't know how much mechanical stress, vibration, and fluid pressure this thing has to endure, but I'd give serious thought to moulding something really cool and casting it in fibreglass. If you mix the colour with the resin, you don't even have to worry about rock chips.
     
  11. Jul 14, 2006 #10

    wolram

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    I did think about fibreglass, but i would have to make moulds, actualy i
    had a job making fairground rides out of fibreglass, but the mould making is an art i do not have.
     
  12. Jul 14, 2006 #11

    Danger

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    You were probably using the 'commercial' method of mould-making, since it was a large company. Making a simple component at home is a lot easier. Just form what you want out of something like paper mache (I use Plasticene for small stuff), then pour a plaster negative mould around it (use release agents such as vegetable oil or wax). When the plaster is dry, coat it with several layers of 1) resin and 2) glass matting. When you have enough layers, toss it into a bin liner and tape the opening around the input tube of your refrigerator compressor. (And if you try to tell me that you don't have a refrigerator compressor lying around as any decent handyman does, I'll never speak to you again. :tongue: )
     
  13. Jul 14, 2006 #12

    wolram

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    Could i not use my hydrovane ?
     
  14. Jul 14, 2006 #13

    NoTime

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    Nice bike.

    I was wondering though.
    If the source of the oil you are complaining about is the engine crankshaft main bearing.
    Won't things get kinda ugly when that oil gets on the drive belt you are thinking of using?
     
  15. Jul 14, 2006 #14

    wolram

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    Its not a problem, the belt and pullies are toothed, the belt can either be run dry or wet, although the oil that does seep past the main bearing is
    minimal it is sufficient to make things messy :smile:
     
  16. Jul 15, 2006 #15

    Danger

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    Maybe, if you tell me what the hell it is. I've never heard of it.
     
  17. Jul 16, 2006 #16

    wolram

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    It is a small vane type compressor, if i want vacuum i install a simple venturie
    type vac generator in line.
     
  18. Jul 16, 2006 #17

    Danger

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    Oh... for sure, then. Even better. Just hold the vacuum until the resin has had a chance to dry. It won't stick to bin liners, so you can just pull it out, trim the flashing, and Bob's your uncle.
     
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