Case hardening the jackshaft

Discussion in 'Transmission / Drivetrain' started by FurryOnTheInside, Mar 20, 2014.

  1. FurryOnTheInside

    FurryOnTheInside Active Member

    Would it be risky to case harden the jackshaft after hollowing it out? I mean would it possibly come out bent?
    Would there be any advantage in hardening it anyway? I'm only asking because I'm bored and I have an over active mind. lol. :p
     

  2. battery

    battery Member

    if they could make a hardend jack shaft it would be benificial as it seems to swell and hammering it out only makes it worse and I'm sure its not good for the bearings.
     
  3. FurryOnTheInside

    FurryOnTheInside Active Member

    They "could" but then so can you or I or the bloke down the road with a torch and a bucket of case hardening compound.
    http://www.technologystudent.com/equip1/heat2.htm

    Not sure why you're hammering it out, lack of gear pullers I guess. I don't think case hardening would make that much difference to swelling due to hammering on the end of the shaft, unless you repeat the process several times to deepen the hardened layer.. going by what I've read.

    Did you hammer your jackshaft out when you changed your 11T for a 10T? :idea: :smash7: :eek:o2ps:
     
  4. FurryOnTheInside

    FurryOnTheInside Active Member

    For case hardening compound try eBay or model railway hobby shops. :idea:

    I was just thinking it might make for a more resilient keyway.. and give me something to show off about haha. :p
     
  5. battery

    battery Member

    I do have a gear puller. but I would have to put a hole in the middle of the shaft for it to grip. and the gear is ver hard to get a grip on. I guess my gear puller is a bit too big.
     
  6. battery

    battery Member

    I have not had any trouble with the keyway as of yet.
     
  7. keatonx

    keatonx Member

    I case hardened a bearing cup that was already hot from brazing on a sprocket, using sugar as the hardening compound. Read it somewhere that it works. I put on tons of sugar so I ate the chunks of caramel/burnt sugar that resulted:jester:

    I probly should've let the brazed part cool and normalize first, but I was just doing it cuz it was already hot.
     
  8. FurryOnTheInside

    FurryOnTheInside Active Member

    But it sounds good though doesn't it? "Myyy jackshaft is hollowed and case hardened" :grin5: lol
     
  9. FurryOnTheInside

    FurryOnTheInside Active Member

    That (bearing races/cups) would be the usual use of case hardening on a HT from what I've read, and is where I heard about it first. I never read about the sugar though.. that's interesting. Though I don't completely believe it haha I'll do some goggling and check it out. Thanks for the tip. :)
     
  10. keatonx

    keatonx Member

    People here on the interwebs have used bone meal, charcoal, joy dish soap, tallow etc. as carbon sources for case hardening
     
  11. FurryOnTheInside

    FurryOnTheInside Active Member

    Ah yes there's "colour case hardenening" where you need to pack the part in your bone meal/leather etc (presumably tallow is for this too) and then heat the whole, before dumping it into the oil-on-water.. but it is easier with commercial compounds, from what I'm reading, as you don't heat the compound, only the part (but this doesn't look so cool because the part comes out dull).

    It might make for less damage to shafts if/when a key is broken.. and I guess if it doesn't distort your bearing cups then it should be fine with shafts too. :)

    Wow the more I read the more complicated this sounds.. still thinking I could get it done inexpensively though.
     
    Last edited: Mar 20, 2014
  12. FurryOnTheInside

    FurryOnTheInside Active Member

    complicated-er and complicated-er... oh well it killed another hour. ^_^ lol
    I will have to ask in the model railway place in town.. mature gentlemen like to do stuff for cheap/nowt just to be able to show off their skills and talk about it. :)

    Found this too


    don't blame me for the music. :goofy:
     
    Last edited by a moderator: Dec 15, 2015
  13. Fabian

    Fabian Well-Known Member

    Why is the end of the jackshaft swelling and hammering out?
     
  14. Fabian

    Fabian Well-Known Member

    If you install the left hand side chain tensioner "with the extra bearing" you would be amazed as to the reduction of jackshaft wear.

    Only one extra bearing yet it adds up to much more than just one extra bearing when it comes to wear.
    In my opinion, just get the left hand side chain tensioner; install the thing and forget about jackshaft wear.
     
  15. battery

    battery Member

    probably all the salt on the road seizing up parts. Im gonna replace everything when I have the money. and both side tentioners.
     
  16. FurryOnTheInside

    FurryOnTheInside Active Member

    Wait.. the jackshaft wears?!?

    Obviously/logically the LHS tensioner is neccesary because the side plate solves the problem of flex in the JS mounting plate (which would presumably be one cause of chain and sprocket wear as well as perhaps chain stability issues, and the upcoming S.B.P. 10T output sprocket would further enhance stability and smooth the power delivery by getting rid of the oscillation that the stock Chinese 10T produces.. but I didn't know the actual jackshaft could wear.
    I think sprocket pullers sound like a good investment, save you hammering on the JS.
    I was only thinking it'd be good to have a hardened JS because if it's soft steel then there would be damage to the keyway if an unforseen event occured.. like getting your pants leg stuck in the chain. Just thought it's easier to replace a key than a keyway and easier to carry a spare key than a spare JS. I didn't even think about wear on the JS.. I mean it spins inside 2 or 3 decent sealed bearings..
     
    Last edited: Mar 26, 2014
  17. Fabian

    Fabian Well-Known Member

    Every mechanical device will wear and it's not a new concept. Given enough time, even the human body wears out.


    With chain guards installed, as per my photos and videos, you will "NEVER" get anything caught in the chain, nor should you get anything caught in the chain.
    If you are getting things caught in the chain, you are doing something wrong, and it's needs to be fixed "FAST".


    You will never have to replace the keyway if assembing and disassembling the jackshaft correctly and with the correct tools for the job.


    The left hand side is supported by a single bearing (which typically has a hammering action placed on it by the acentric 10 tooth Chinese output shaft sprocket) you will find that this vibration hammers away at the left hand side bearing and also the jackshaft that runs inside the bearing.

    When you add a third bearing into the system on the left hand side it effectively adds 100% more bearing capacity into the left hand side of the jackshaft. This gives a dramatic reduction in not only bearing wear, but jackshaft wear.
    For this reason, the left hand side chain tensioner is an essential, or "should be" considered an essential part of the shift kit, even though it is an optional accessory item.

    I am getting towards 3,000 kilometers (1,860 miles) on my current shift kit shaft and bearings, with the installed left hand side chain tensioner. As things are, it is showing no significant signs of shaft or bearing wear.
     
  18. FurryOnTheInside

    FurryOnTheInside Active Member

    Yeah I suppose the JS slips minutely side-to-side within it's bearings as a result of it's tilting (shimmying?? lol Idk what to call that movement) due to frame flex.. though that's now pretty much solved with the LHS tensioner, and most of the remaining tinyy amount of flex there should be eliminated by the upcoming S.B.P. 10T engine output sprocket.

    Hey I did say "unforseen". Could be a final chain jamming and snapping, whipping up and getting caught under the RHS chain, for instance. Or umm, a stone thrown up from the road. Or some other unforseen act of God lol, I just thought maybe the keyway should be very resilient. (I was only looking into it because I was bored and just wondering.)

    Oh I can see from the shape of the JS mounting plate that the left hand side chain tensioner is essential. That shape is great for resisting flex in one direction (approx the line of the RHS chain) but not a great shape for resisting flex in the other obvious direction, so the LHS tensioner side plate deals with that, supporting the JS much further away from it's middle so the mounting then must be a heck of a lot stiffer.
    (Not saying there's anything badly made about the shift kit mounting plate, just that there's obvious limits to the stiffness you can expect with that shape piece of metal holding two bearings quite close to the middle of the shaft, with the two sprockets being out at the ends.)
     
  19. Fabian

    Fabian Well-Known Member

    You have made a perfect assessment of the situation, and in practice, that is exactly how the extra bearing and side plate give additional support and load bearing capacity.

    In many ways, when you install the left hand side chain tensioner, you are getting two things for the price of one: a chain tensioner and an additional jackshaft support structure; giving 100% more load bearing capacity to the left hand side assembly - a win, win situation without any negatives.

    Another less obvious fact is that the left hand side tensioner plate effectively becomes a chain guard; preventing your jeans or other clothing from being caught in the chain and sprocket.
    I find this overlooked fact to be just as important as the other benefits that come with the installation of the left hand side chain tensioner, so it is now a,

    win, win & win situation - three things for the price of one!
     
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