401 Platter Bearing

301, 401, plinths and assorted idler stuff
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Greg
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#31

Post by Greg »

Thank you Paul, your access to Darren is good to know. I would like to service his bearing I use so any information, even supplied privately would be gratefully received.

Further bearing thoughts. To assess how good or not the tolerance of your bearing is, with it solidly mounted in the chassis and the platter firmly fitted, apply your left and right thumbs across the width of the platter and see how much rock with alternating pressure you get. The more movement, the more it is worn. I don't have a scale to suggest when using this test, when you need to refurbish your bearing. It's simply an engineering 'feel' thing. Your head will tell you when it is too sloppy or sufficiently tight. Obviously, excessively and recognisable movement would suggest a need for a refurbishment. I hope that helps a bit more.
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Paul Barker
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#32

Post by Paul Barker »

I get the principle of the test.

Wandering if the bushes the rod and the thrust seat can all be made from Teflon.
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#33

Post by pre65 »

Paul Barker wrote:I get the principle of the test.

Wandering if the bushes the rod and the thrust seat can all be made from Teflon.
Not sure that would be a good idea. I doubt a Teflon spindle would be rigid enough.
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#34

Post by Greg »

Paul Barker wrote:Wandering if the bushes the rod and the thrust seat can all be made from Teflon.
Yes, probably completely possible in my view although as Philip suggests, assuming your 'rod' means spindle, that probably would be impractical to do. From an individual one off DIY perspective, if you have the means to produce closely toleranced Teflon bearing sleeves and thrust bearings etc, it might work, and let's be realistic here, are you in a position to achieve this? If you are, how will it sound? That is a question that can only be answered after experiment. I doubt you have the time or inclination to experiment to that degree. Always to much to do. Better to buy into whatever is good in the market and live and enjoy it.
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#35

Post by Paul Barker »

It is easy to do, a little time consuming. Turning it to the exact right size to fit bushes. Bushes taken to exact size with a reamer. But a lot cheaper in time than the time it would take to earn the income after tax to buy aftermarket versions.

Would it sound better? Might not. Stock bearing sounds good to me. Exploring ideas is all I am doing.

Spindle rigidity? Bigger problem I hadn't thought of is not so much this, because it is held rigid by the structure Top and bottom bushes in a rigid metal casing, support at the bottom by the thrust bearing. No the problem is insufficient friction in the spindle to glue itself to the platter, normally achieved with a taper fit of two similar metals. There would be slip. It could be keyed and the platter keyed to accept it using a shaper. I don't have one but could get that done. Would still need the taper fit to make platter fit exactly 90 degrees to it all the way round 360 degrees, the key is to prevent slip around the 360.



It's main advantage : little friction, is it's downfall.

The easier option is make new metal parts with finer tolerances so you aren't R and D'ng materials technology.
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#36

Post by pre65 »

I think that the idea of having a spindle and bearing of the same material is fundamentally flawed.

Sorry. :(
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#37

Post by Paul Barker »

You probably know better than me.
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#38

Post by hifimaster »

Greg, can I take this opportunity to correct a statement of yours regarding my bearings. My bearings have always been £450. The Redbeard bearings were nearly £600. We stopped doing them because to be quite frank, they were hit and miss regarding quality.
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#39

Post by Greg »

Hi Dom,

My apologies for posting misinformation.

Greg
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#40

Post by Reffc »

Just thought I'd post a warning about the bronze after market bearing kit mentioned earlier on this thread. When I first fitted mine and checked it after 6 months, everything seemed fine.

A year later and removing it today for my annual service of the 401 and I noted a slight wear dimple (very slight but there) on the base of the spindle caused by the bearing. The bearing had a very slight (.2mm?) flat, only just visible to the eye.

I've removed and cleaned down the spindle, and put the original thrust bearing back in despite the flat worn on that, and used 0W30 fully synthetic oil in the well. Replacing everything and it runs surprisingly quietly bar some rumble from the idler which always seems to be the case after servicing until everything beds back in again.

I thought it worth the warning in case others use this bearing and suffer the same issues. It seems that the "hydraulic" version from Germany may be the better option, if expensive or otherwise find an original thrust pad and just use decent oil.
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#41

Post by Greg »

A good point very well raised, Paul. Having met with Dominic and Natalie (NWA) over the weekend and the knowledge I have gleaned at Owston, I retract my previous recommendation of the bronze ball bearing after market thrust pad kit and like you, also recommend sticking with the original Garrard thrust pad coupled with good lubrication. It would be good for Dominic or possibly someone else to do a critical review on the latest so called hydraulic option you mention. Incidentally, Dominic recommends using oil with no additives whatsoever in order to retain the porosity of the sintered bronze outer bearing sleeves and therefore not to use oil designed for the automotive industry. He can supply a good oil that meets his required specification on this.
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#42

Post by Reffc »

Greg wrote:A good point very well raised, Paul. Having met with Dominic and Natalie (NWA) over the weekend and the knowledge I have gleaned at Owston, I retract my previous recommendation of the bronze ball bearing after market thrust pad kit and like you, also recommend sticking with the original Garrard thrust pad coupled with good lubrication. It would be good for Dominic or possibly someone else to do a critical review on the latest so called hydraulic option you mention. Incidentally, Dominic recommends using oil with no additives whatsoever in order to retain the porosity of the sintered bronze outer bearing sleeves and therefore not to use oil designed for the automotive industry. He can supply a good oil that meets his required specification on this.
I'm not so sure about the oil Greg. In the automotive industry, it's still used where bronze bush bearings are considered. I have my doubts whether any refinery or oil company produces oil specially for the hifi industry, and even some TT oils contain Molybdenum. I do have access to TT oils (trade) so may look into it further. For now, I'll continue to use fully synthetic 0w20.
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#43

Post by hifimaster »

Having spoken to oil refiners myself, there are many many kinds of oils available some incredibly pure and all oils designed for specific uses. There are industries that need oils that are compatible for my use when restoring the Garrards.
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#44

Post by Reffc »

hifimaster wrote:Having spoken to oil refiners myself, there are many many kinds of oils available some incredibly pure and all oils designed for specific uses. There are industries that need oils that are compatible for my use when restoring the Garrards.
Hi, yes, I understand that. The point though is that turntable spindles are hardly a unique or demanding lubrication environment. If you look at the list of oils that many manufacturers prescribe, some specify automotive SAE20 or 40 synthetic oils for standard spherical bearings and something like light machine oil (SEA20) for spindle lubrication. Additive free sewing machine oil is often used. The additives on most automotive oils are there to combat corrosion caused by by-products of the combustion process and won't harm bearing surfaces. I think perhaps that too much is sometimes read into these oil specifications for turntables.
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#45

Post by Neal »

The high sulphur content in gearbox EP oil can damage sintered bronze bearings over time, however, engine oils should be OK. Personally I use a straight SAE oil on the GL-99 and the recommend Panasonic oil which is quite thin on the SP-10
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