Why are most platter / spindle bearings plain Bush bearings. Why aren't roller bearings employed?
Thanks for your response, Jeff. That was my initial thought. However, correctly set up I don't believe that would be the case. Especially if taper roller bearings are used. That said, I've not researched to see if taper roller bearings are available for such small diameters.
Noise. Too many contact points. A "stick in a hole" bearing has only one pressurized contact point with the shaft submerged in oil or lubricant so it will always be quieter than a roller bearing with multiple rolling elements. The only thing quieter is probably air bearing, which is employed in some really expensive turntables, like Techdas and Micro-Seiki.
There might be other clever designs out there that can provide similar performance at a cheaper price.
There might be other clever designs out there that can provide similar performance at a cheaper price.
Even if you find some tapered bearings, I'm not sure there's any advantage over single row bearings. I've sourced quite a few small series bearings (8-10mm & 3/8" bore), and never came across any tapered bearings that size.
It's going to be an uphill battle IMHO. Ever wonder why commercial turntable manufacturers don't use roller bearings?
jeff
Took me about 3 minutes to find Timken's catalog. (Timken invented taper roller.)
https://www.timken.com/wp-content/uploads/2018/10/Timken-Tapered-Roller-Bearing-Catalog_10481-1.pdf
8MB PDF
PDF page 84 (paper page 82) shows taper roller down to 0.3125" ID. Rating to 4 ton static 1 ton dynamic.
The general problem with ball/roller bearings in a phono is the balls/rolls can NOT be perfectly round within the amplitude we use for phono recordings. It may be few-microInch but the lumps repeat multiple times per revolution, and not even consistently (slip). The plain bearing may have far more slop, but it is a much simpler affair without lumpy balls.
Ball/roller have virtue for HIGH loads and HIGH speeds or where lubrication is infrequent. Unless you stack a dozen tractor flywheels as your turntable (idea!!) you don't have load, and 33rpm is far off the charts for most bearings.
Philips developed "plain" bearings with spiral groove for gas, oil, and grease.
https://www.americanradiohistory.co...-Review/60s/Philips-Technical-Review-1963.pdf PDF page 260
There's also gas-under-pressure and magnetic levitation/centering.
Please ignore my first reply. It was wishful thinking and I hadn’t given much thought to my response.
Indeed, tapered roller bearings have the advantages of a longer contact area to support larger loads and a geometry which provides the capability of carrying large combined radial and thrust loads. Neither of these advantages are relevant to the turntable application, where loads and speeds are miniscule by the standards of rolling element bearings. Hydrodynamic bearings, which avoid direct surface to surface contact by taking advantage of the viscosity of an interposed lubricant film, are the optimal configuration here.
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