Another oil thread

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  • beaglebasher
    beaglebasher
    2 years ago
    I am having problems at work with a small gearbox that is destroying itself every time I build it. 
    They are worth 12 grand each and we have fucked at least 10 of them. We have built 20 of them.
    It has been an ongoing process for two years and I am ready to hear any suggestions.
    The  teeth on the output drive are getting stripped off.
    I am thinkig about  trying the Redline shockproof stuff that some people recommend.
    Where can you buy it?

  • beaglebasher
    beaglebasher
    2 years ago
    Quoting Ratbob on 29 Apr 2021 02:49 PM

    If you’re not looking for a walk in store, these have it online

    Supercheap sell Redline products.

    Thanks for that Rb. I was in Supercheap  on Thursday looking for it but  they  didn't have it. 
    I ended up buying Penrite  80W-140
    gear oil and put  it in the gearbox I had built that  morning.  
    We  put it on the  test bench  and  it lasted less than  10 minutes before it shit itself. Again.
    This particular gearbox has design issues that we are addressing but I reckon if we use the best oil we can find it should give us a chance. 
    I will  order some off Ebay  and give it a go. 

  • Timmy
    Timmy
    2 years ago
    Hmm oil aside, somethings not right here.  I don’t think it’s the oil that’s the problem.  But I must admit, I know absolutely nothing about the gearbox you are working on.  
  • Smokey61
    Smokey61
    2 years ago
    Sounds like oil is not going to fix your problem.
  • B0nes
    B0nes
    2 years ago
    I buy Redline Shockproof from Amazon. Arrives in 2 days from an Aust supplier.
  • fatbat
    fatbat
    2 years ago
    I’m with Timmy and Smokey mate. Sounds like a design flaw perhaps 
  • beaglebasher
    beaglebasher
    2 years ago
    Quoting fatbat on 03 May 2021 06:38 AM

    I’m with Timmy and Smokey mate. Sounds like a design flaw perhaps 

     Youse are right. The design is the problem.  Basically it was designed too small for the job  it has to do but we have inherited this headache.
    And it is a fukin headache.  We have made a few modifications but it takes weeks to get the new components back from the machinists and I have no confidence in the modifications that have been made. 
    That reminds me,  better get on ebay.

  • steelo
    steelo
    2 years ago
    Did you contact my mate bb. 
  • beaglebasher
    beaglebasher
    2 years ago
    Just got your message steelo.
    Is your mate into a  serious headfuck ?
    Just for the record I just ordered a litre of the Redline stuff off ebay but like a few other people I dont think it will solve the problem.
    I am hoping it might help but.
    Thanks again steelo
  • Krash Kinkade
    Krash Kinkade
    2 years ago
    Quoting beaglebasher on 03 May 2021 09:32 AMedited: 03 May 2021 01:02 PM

    Just got your message steelo.

    Is your mate into a  serious headfuck ?
    Just for the record I just ordered a litre of the Redline stuff off ebay but like a few other people I dont think it will solve the problem.
    I am hoping it might help but.
    Thanks again steelo

    BB , thought I'd mention, there is a light shockproof redline oil, & a heavy shockproof redline oil. all I have used & can confirm its good gear box oil is the Heavy Shockproof. I think it was originally made for Top Fuel drag raceing ( nitro burners ). 
    But it's not magic.
    Have you got any picture's of the gear box & the broken parts?
  • beaglebasher
    beaglebasher
    2 years ago
    That should give you an idea of what is going on. 
  • steelo
    steelo
    2 years ago
    I'm no engineer but if there is a lot of power going through those gears, helical cut gears are going to spread the load across multiple teeth instead of one at a time.

    From a google search.
    Helical cut gears are stronger because they have far more surface areas and due to the helical design, more of them are in contact at the same time, spreading the load. ... Making more than two teeth mesh at the same time on a straight-cut gears would wear out the teeth and also make them less durable.
    There is a power loss with Helical but they are quieter.
  • beaglebasher
    beaglebasher
    2 years ago
    Youre all over it steelo !
    The basic design  has been  challenging the gearbox from day 1.
    The problem isnt so much too much power or torque.  The small shaft spins at 10,000 rpm at full speed and it runs nice and smooth at 10,000 .
    Getting there is where we are having the problems. At roughly 6000 rpm it starts to rattle and vibrate. At 7000 rpm it tries to jump off the bench.
    At 8000 you can hear it destoying itself. It then suddenly smooths out and runs smooth but when we strip it down for a look all the teeth on the final drive are fucked.  
    We have arranged a meeting with a specialist gear mob on Friday. I reckon they are gonna tell us what we already know.  " it is fucked "
  • brucefxdl
    brucefxdl
    2 years ago
    Quoting beaglebasher on 05 May 2021 12:53 AM

    That should give you an idea of what is going on. 

    if i didnt know better id say the pinion and spur gear are not running parrallel under load ,as the side of the spur at the pinion end appear to have had deeper contact,leaving the other side with shallow, to no contact or depth.jmho.are the components sitting as they would line up when assembled ?
  • drod
    drod
    2 years ago
    has the output gear been heat treated? what steel are you making it from? 
  • beaglebasher
    beaglebasher
    2 years ago
    They are  not lined up as they are in service  bruce.  The  spur gear should be the other way around  ( the  broken  teeth   run near the  bearing ). I noticed that after I took the photo but didn't think anybody would  notice !

    We have  tried  two  different heat treatments drod. The  original   manufacturers heat treatment  and something called  nitrile hardening. 
    The Redline  Heavy  got delivered yesterday so I might give it a go next week. 
  • Wideglider
    Wideglider
    2 years ago
    With this sort of catastrophic failure occurring regularly - I don't think using a different lubricant is going to save you here!
    It would appear that simply the gearbox is not up to the job/load being forced upon it. 
  • Far Canal
    Far Canal
    2 years ago
    Quoting beaglebasher on 08 May 2021 12:34 PM

    They are  not lined up as they are in service  bruce.  The  spur gear should be the other way around  ( the  broken  teeth   run near the  bearing ). I noticed that after I took the photo but didn't think anybody would  notice !


    We have  tried  two  different heat treatments drod. The  original   manufacturers heat treatment  and something called  nitrile hardening. 
    The Redline  Heavy  got delivered yesterday so I might give it a go next week. 

    "The  spur gear should be the other way around  ( the  broken  teeth   run near the  bearing )."

    I suspected that may have been the case. Been wondering if the the spur gear (the big one) is too wide and is getting snagged up in the fluted end (nearer the bearing) of the slimmer gear as that is obviously where things are going wrong. Maybe it could be worth somehow machining the thickness of that big one down a bit and giving it a try?. It'd have to be easier than extending the fluting.
    Perhaps even grinding a small radius on the end of the spur gear to eliminate any interference on the fluted end.
    Just a thought old boy.
  • beaglebasher
    beaglebasher
    2 years ago
    That is a fair point you are making there FC but  we have  measured it carefully and there is at least  2mm clearance between the end of the gear and the start of the  flute.  
    We had a meeting with specialist engineers  on Friday but unfortunately I couldn't get there . One of the  other blokes went instead so hopefully I will find out more tomorrow. 
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