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LP12 Spindle

Discussion in 'd.i.y.' started by Vinny, Aug 10, 2017.

  1. Bob B.

    Bob B. pfm Member

    I agree totally. Then you are completely removing any variables. BTW I have just done some research and the temperatures are suggested as being around 700 degrees fahrenheit at the point.
  2. Tony L

    Tony L Administrator

    Also worth remembering there are many variations on the bearing housing used over the years. I've seen a lot of LP12 bearings (IIRC I've owned 12 LP12s!) and seeing a little bearing wear is not uncommon at all, nor is it something to get hugely paranoid about. I've certainly found no correlation between perceived visual condition of the bearing tip and whether it was a good sounding example, i.e. a tiny flat or wear spot isn't a disaster IMO. I never did more than clean and relube. I've only seen one really worn bearing, a pre-Cirkus one that had a real flat-spot. I chucked that one out as I thought it unfair to eBay it. I guess it had run dry at some point. All the others were just what you'd expect from a well-cared for deck that had played a fair number of records.
  3. Mark,
    For once we agree on something .:cool:
    If people didn't just drop the inner platters in and lowered them carefully and used the right oil in the first place ???
  4. I have been using a Tranquility (The only aftermarket none Linn bit of kit on my deck) for months now and love what it does.
    It's almost sexual watching the way the inner platter lowers itself down into the bearing tube.:cool:
  5. Gaius

    Gaius Trade: Stiletto by Tangerine

    Right. A new dawn? :)
  6. flatpopely

    flatpopely Prog Rock/Moderator

    I'm new to the TQ club ........ game changer IHMO!
  7. sq225917

    sq225917 situation engineer

    Hundreds of degrees? Hardly. The spindle would jam tight. There's too much metal mass in the spindle for it to raise by more than a few degrees at the tip.
  8. Robert

    Robert Tapehead

    Indeed....and we're only talking 33/45 rpm!
  9. chiily

    chiily PFM Special Builder

    Agreed. I can't understand Bob's 700degF number. Let's see the maths...
  10. TPA

    TPA Trade: Tiger Paw

    Funny you should say that. I've done some calculations to determine what the original force on the spindle point is, clearly there is some grey area in determining what you believe the cross section of the point of contact to be, but you are certainly in the realms of many many tonnes per square inch. (PSI = pounds per square inch, so this is considerable). Understanding the effect of lubrication, and how the materials act at those pressures is complex. The area of science relating to this is Tribology.
  11. Bob B.

    Bob B. pfm Member

    Oh dear. Typo. I must stop drinking a couple of bottles of red on a Friday night. It was supposed to read 70 degrees. No maths involved. Purely found in some of my old notes from a long time ago. Don't read my posts late on a Friday night. Cheers guys.
  12. Tony L

    Tony L Administrator

    I've yet to observe a turntable main bearing housing at anything above ambient room temperature. I'm sure if it was 70% at the contact point that would radiate out and warm the housing. Motors are whole other things, the big old idler decks I like do run very warm.
  13. Barrymagrec

    Barrymagrec pfm Member

    If the 70 degrees is correct it would only be at the tip, heat dispersal through the shaft and thrust would be virtually instantaneous, apart from anything else, if there was sufficient friction to warm up the whole bearing housing and shaft to 70 degrees you would need a much more powerful motor to drive it and the belt would snap.
  14. TPA

    TPA Trade: Tiger Paw

    I have no idea what the tip temperature is but the mass of the rest of the spindle and platter will soak that up and of course the whole assembly is running in an oil bath so that will reduce temps considerably. Either way there is little chance of the whole bearing generating much heat above ambient temperatures. If you were to run it at a much higher rpm and remove the oil then you'd find temperature and wear rate would rise significantly.

    The factors that contribute to the bearing running quietly also involve things like how concentrically the tip is located which would increase scrub etc. Probably one of the reasons some manufacturers like to use a ball bearing against a flat spindle surface, potentially a cheap way to do this (if you can correctly locate the ball)
  15. Bob B.

    Bob B. pfm Member

    Ok to clarify. I am giving you data I got from the numerous Linn guys I spoke to at the time. I visited the factory in Drakemire drive more than a few times. The figure of 70 farehheit was the heat generated at the point contact and was what the lubricant had to deal with at that point. I agree the mass off the spindle plus the inner/ outer platter and the amount of oil in the housing would dissipate this to ambient temp. I was also imformed at the time that it was normal for a small part of burnt oil deposit was quite normal to be seen on the end of the tip.
  16. Mynamemynaim

    Mynamemynaim pfm Member

    Obviously....As you don't agree with me...
    ( By the way ..it's No idea ..not know)
  17. chiily

    chiily PFM Special Builder

    I'm still intrigued by the oil that has hardened due to heat now we've established that we are talking about 70degF.
  18. RustyB

    RustyB Registered Ginga

    Anyone know what oil is recommended for the very early (bronze coloured) bearing?
  19. nitrous

    nitrous pfm Member

    Could it just be a blob of the molyslip that has accumulated and not burnt oil? The stuff does tend to settle out of the oil over time, which is why you have to shake the bottle of Linn 'black' oil to disperse it.
  20. Tony L

    Tony L Administrator

    There is also a good chance a different oil has been added without flushing the original out properly in very old bearings, e.g. there might be a mix of organic and synthetic or whatever in some bearings. Linn bearings are far harder to clean than the old Garrard/Thorens/Lenco types with their detachable thrust plates. To be honest I never found a technique I was happy with.

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