401 Platter Bearing

301, 401, plinths and assorted idler stuff
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hifimaster
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#46

Post by hifimaster »

Because there are so many oils and additives out there I advise not to use motor oils etc.
Graeme
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#47

Post by Graeme »

Just too add a little more confusion, there are non addative motor oils available for the classic car owners.

Also, as we touched on at owston dom, different bearings will have different requirements due to clearance and materials.

One last thing about the weights of motor oils, many people dont understand what they mean.

For example, 10-40.
the first number is the viscocity when cold.
The second number means when hot it thins to the same extent a 40w would rather than a straight 10w.

As our bearings wont get hot the hot weight means nothing so a 10w, 10-20, 10-30, 10-40 etc would all act the same in a cold aplication. We can ignore the second number.
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#48

Post by Graeme »

someone mentioned moly, is this not good for TT bearings? I have a few amazing moly greases for use in my air rifles. Sure is slippery stuff!

Does it block up sintered bearings? Ok in bronze bearings? Or just generaly too noisy as the moly is basicaly a particulate right?
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#49

Post by Reffc »

Neal wrote: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
Agreed. I know that some folk use gearbox oil but I wont. Having spoken to one of the chaps at Michell and asked his advice, I was told "Mobil 1 0W30 or 15W50" are both fine and what they use themselves.

I oil the spindle in sewing machine oil very lightly, but I use synthetic engine oil in the well. The Gyro has been running almost daily like this from new and the bearing surfaces are mint so I have no doubts as to the suitability of that oil. Anyone trying to sell me a £20 5ml bottle of "TT Oil" is going to tell me that motor oil isn't suitable. I shall continue to use it and my TT won't be any the worse of for it.
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#50

Post by Reffc »

hifimaster wrote:Because there are so many oils and additives out there I advise not to use motor oils etc.
Perhaps a bit too simplistic? There are specific motor oils which are perfectly suitable.
Graeme
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#51

Post by Graeme »

This is getting slightly de-railed :).

Whats the michell bearing made from?

Rega specify gear oil due to the high pressure point on the ball, but there bearings arent sintered bushes.
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#52

Post by Neal »

There are other oils you can try depending on the bearing and materials. IE you can experiment with a 'grease' like the rocket fishing reel high viscosity oil. There is a speed analysis thread over on PFM that has been running for some time and on some decks a heavy liquid grease showed an improvement over a thin oil. I experimented with this on a couple of DD decks including my SP10 but there was no improvement, intact they where slightly worse so thiinner seems to me to be better for DD while thicker may be better for belt drive.....
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hifimaster
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#53

Post by hifimaster »

The Gyro does not use sintered bushes, plus it uses an Archimedes screw action to pump oil continuously from its oil well.
Different manufacturers will have their own recommendations.
The oil I use I know can be used safely with any turntable. The tolerance of the bearing is just as important as the type of material it is made from.
For my own bearings I use a very light and pure sewing machine type oil, otherwise frequency extension will be affected.
Using grease in a non grease bearing is not advised on purely sonic terms, unless the wear or tolerance allows it.
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Mike H
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#54

Post by Mike H »

Oh no it's degenerated into an 'oil thread' Image



:lol:
 
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Neal
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#55

Post by Neal »

hifimaster wrote:....
Using grease in a non grease bearing is not advised on purely sonic terms, unless the wear or tolerance allows it.
Heavy grease yes but nobody was advocating that. TG Rocket Fuel Red is a liquid 'grease' probably around 2000cst or less so no where near a heavy grease.
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#56

Post by Reffc »

Graeme wrote:This is getting slightly de-railed :).

Whats the michell bearing made from?

Rega specify gear oil due to the high pressure point on the ball, but there bearings arent sintered bushes.
Gear oils are not normally recommended for sintered bearings or any yellow metal bearings due to the corrosive additives some of them use. Motor oils are usually fine. The only issue with some motor oils tends to be the amount of detergents used and there is some anecdotal evidence supporting visible pitting to bearing shafts after using them (although it is never confirmed exactly what oils were used nor for how long) but there's rarely any suggestions put forward as to why the pitting occurs.

For most parts, a good motor oil is fine for yellow metals. Bike and car enthusiasts will tell you that many engines (especially classic bikes and cars) use sintered and phosphur bronze bearings. The viscosity thing is something I'm not too convinced on though for TT bearings. I've read numerous posts on forums advocating thinner oils but for slow moving bearings, it's shear that matters and not necessarily viscosity. I would have thought that any oil though from an SAE0 to SAE50 was fine.

The Michell main bearing consists of a steel ball upon which a hardened steel shaft rides, pretty conventional stuff really. It does have a turned bronze inverted bearing sleeve through which the shaft slides so in this respect, similar considerations are shared with the 401, and Michell are happy to use motor oil.
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Ali Tait
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#57

Post by Ali Tait »

Changed back to original thrust plate as per Dom's advice. Can't say I noticed any difference to the sound..
low pitch
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#58

Post by low pitch »

I bought the original Kokomo thrust bearing for my 401 and didn't end up fitting it. The thing I had reservations about (apart from wear), was the possible eccentricity of the bearing point. There is nothing to accurately centralise the ball, as the fit of the spigot is quite loose inside the housing. No doubt this is why classic designs of this type have the ball held by a cup in the spindle.
martin
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