They're good running against steel raceways when lubrication is non-existent or marginal. Under those conditions if using steel balls, micro asperities on the balls and raceways will weld together under high localized pressure and then break apart generating small steel particles and the bearings will destroy themselves in short order. With ceramic, no welding occurs amd bearing life is vastly improved under those sort of harsh conditions. Its also why ceramic is a good choice for a turntable thrust bearing.
There's complete misconception on what type of materials are better used for holding a platter .With the normsl size balls, if the platter is below 25kg you will barely have any friction problem in the next 30 years with the regular steel ball.Besides a good quality 8...10 ball bearing using 5 mm balls can be used at high speeds with loads of up to 2 tons(2000kg...) while aluminium oxide(9.2 toughness on Mochs scale and only second to diamond) and some of the ceramics are way more abrasive to the normal steel than steel itself so they won't be really a better choice than steel unless they get in touch with a similar ball attached to the other part that's rolling against .
What many ignore is that actually :
1.we WANT as much FRICTION as possible and predictable to occur in most turntables because the friction is fighting oscillation in the motor speed regulator feedback or belt elongation as much as the inertial mass does.If it's an asyncronous shadow poles motor the more drag you have the more predictable the pole slip is and also you will have fewer chances to complain about stylus drag .
2. Steel balls are conductive and help releasing the electrostatics to the chassis ground .We need steel balls making contact with the platter as much as we need a conductive mat instead of a corck mat...
What many ignore is that actually :
1.we WANT as much FRICTION as possible and predictable to occur in most turntables because the friction is fighting oscillation in the motor speed regulator feedback or belt elongation as much as the inertial mass does.If it's an asyncronous shadow poles motor the more drag you have the more predictable the pole slip is and also you will have fewer chances to complain about stylus drag .
2. Steel balls are conductive and help releasing the electrostatics to the chassis ground .We need steel balls making contact with the platter as much as we need a conductive mat instead of a corck mat...
I could see there being a significant weight advantage for large series ceramic caged roller bearings, versus steel. The ones we were dealing with were small, and weight wasn't an attribute we really cared about. They were also quite a low grade, maybe ABEC1 or 2, but they were cheap. We called them "cheese grade". 🙂
jeff
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How about shock loads and vibration?
And ceramic itself is a vast subject.
I have not checked, please see for yourself how many famous bearing makers are offering ceramic bearings with life vs. load curves, guaranteed performance, in shaft sizes exceeding 25 mm.
It seems Koyo and SKF do make ceramic ball bearings in complete assemblies, the balls are not sold as a separate item.
SKF even makes those for wind turbines, Koyo makes them in small sizes.
But I would not use them in a cement kiln.
So if you do buy loose balls, your mileage may vary.
And ceramic itself is a vast subject.
I have not checked, please see for yourself how many famous bearing makers are offering ceramic bearings with life vs. load curves, guaranteed performance, in shaft sizes exceeding 25 mm.
It seems Koyo and SKF do make ceramic ball bearings in complete assemblies, the balls are not sold as a separate item.
SKF even makes those for wind turbines, Koyo makes them in small sizes.
But I would not use them in a cement kiln.
So if you do buy loose balls, your mileage may vary.
Steel Ball Bearings are Capable of Conducting electricity, where as a Non-Steel Ball Bearing can be Non Conductive.
In a Steel Balls Static Electricity can manifest and transfer through the Steel Ball as a current.
When a lubricant is in use, that is Non Conductive, and the Hydrodynamic Condition is at its Poorest or Boundary Lubrication has manifested, the discharge of the electricity has the capacity to produce a Substantial Heat within the environment, which the heat can cause welding of the surfaces in close contact.
The impact of the Welding occurring is that 'pitting can be produced' on the metal surfaces.
As the pitting is now showing as a surface imperfection and the imperfection is most likely to be at a shared location on the opposing surfaces and these two imperfections that will most likely come into contact, as a result of Poor Hydrodynamic Lubrication or a Boundary effect Lubrication having manifested.
There is then the likelihood that increased noise is the outcome, that is most likely going to reduce the effectiveness of the Bearing and impart unwanted energies toward the Stylus.
The question that is a unknown is that the environment within a Bearing Housing, and the rotations of the Spindle might not be able to cause the conditions under discussion, but the conditions are encountered by a Bearing and these conditions can occur in a Bearing Assembly.
With these considerations in mind, a 'Prevention is better than Cure' approach of thoughts on the subject will be a good practice.
The effects of the impact of electricity can be alleviated if the condition is created that prevents the produced electric current passing through the Steel Ball Bearing.
One solution that can be investigated is to use a method of grounding, another solution is to use a non conductive Ball Bearing Material at all the interfaces with the Steel Spindle, such as a Ceramic Ball, and Bush Liners.
There are other Ball Materials such as Thermoplastics, Glass and Jewel and Bush Liners that can be produced from Thermoplastics.
One short cut that might be seen as fix all method is the idea of using a conductive lubricant.
The use of a conductive lubricant is quite difficult to assess for its value, as the most effective method of lubrication within a Patter Spindle Bearing is to have the condition produced where Hydrodynamic Lubrication is occurring, the requirements to achieve this condition has a whole science attached to it and is not easily achieved to last a reasonable length of time and definitely not easy to prove the condition as being permanently maintained.
The condition can be created by any individual for a temporary period, and this period can vary from a few days to a few weeks, but the likelihood is that the temporary condition will after a short period of time develop into a Boundary effect lubrication, and the Spindle / Sacrificial Parts at a interface 'will' come into contact.
My personal take on this at present is that a Bearing Housing Environment that is produced that can contain a fill of a lubrication to the level of the Upper Bush, is 'possibly' a method that will ensure the Lubrication is remaining in contact with the critical interfaces and Hydrodynamic Lubrication will be present and maintained.
If the metal sacrificial parts within a Bearing Housing are replaced with a Non Metal alternative, this will ensure that no Metal/Metal contact is developing.
The benefits of no Metal/Metal contact, will ensure, the Spindle, that is the most valuable item in the assembly of the bearing, is maintained in a prime condition and that noise produced from metal/metal is not of a concern.
The Additional knowledge that metal mechanical artefacts are not depositing in the Bearing Housing and creating an abrasive at the critical interfaces, causing unwanted damages will no longer be a concern and unwanted energies produced from metal/metal contact or abrasives, are not being transferred to unwanted locations are also attractive conditions to have considered to be created.
There will also be one more condition created when a careful selection is made for a Sacrificial Part that is Non Metal, and a suitable environment is produced for their placement, which is the Co-Efficient of Friction for the overall assembly is going to be improved.
In a Steel Balls Static Electricity can manifest and transfer through the Steel Ball as a current.
When a lubricant is in use, that is Non Conductive, and the Hydrodynamic Condition is at its Poorest or Boundary Lubrication has manifested, the discharge of the electricity has the capacity to produce a Substantial Heat within the environment, which the heat can cause welding of the surfaces in close contact.
The impact of the Welding occurring is that 'pitting can be produced' on the metal surfaces.
As the pitting is now showing as a surface imperfection and the imperfection is most likely to be at a shared location on the opposing surfaces and these two imperfections that will most likely come into contact, as a result of Poor Hydrodynamic Lubrication or a Boundary effect Lubrication having manifested.
There is then the likelihood that increased noise is the outcome, that is most likely going to reduce the effectiveness of the Bearing and impart unwanted energies toward the Stylus.
The question that is a unknown is that the environment within a Bearing Housing, and the rotations of the Spindle might not be able to cause the conditions under discussion, but the conditions are encountered by a Bearing and these conditions can occur in a Bearing Assembly.
With these considerations in mind, a 'Prevention is better than Cure' approach of thoughts on the subject will be a good practice.
The effects of the impact of electricity can be alleviated if the condition is created that prevents the produced electric current passing through the Steel Ball Bearing.
One solution that can be investigated is to use a method of grounding, another solution is to use a non conductive Ball Bearing Material at all the interfaces with the Steel Spindle, such as a Ceramic Ball, and Bush Liners.
There are other Ball Materials such as Thermoplastics, Glass and Jewel and Bush Liners that can be produced from Thermoplastics.
One short cut that might be seen as fix all method is the idea of using a conductive lubricant.
The use of a conductive lubricant is quite difficult to assess for its value, as the most effective method of lubrication within a Patter Spindle Bearing is to have the condition produced where Hydrodynamic Lubrication is occurring, the requirements to achieve this condition has a whole science attached to it and is not easily achieved to last a reasonable length of time and definitely not easy to prove the condition as being permanently maintained.
The condition can be created by any individual for a temporary period, and this period can vary from a few days to a few weeks, but the likelihood is that the temporary condition will after a short period of time develop into a Boundary effect lubrication, and the Spindle / Sacrificial Parts at a interface 'will' come into contact.
My personal take on this at present is that a Bearing Housing Environment that is produced that can contain a fill of a lubrication to the level of the Upper Bush, is 'possibly' a method that will ensure the Lubrication is remaining in contact with the critical interfaces and Hydrodynamic Lubrication will be present and maintained.
If the metal sacrificial parts within a Bearing Housing are replaced with a Non Metal alternative, this will ensure that no Metal/Metal contact is developing.
The benefits of no Metal/Metal contact, will ensure, the Spindle, that is the most valuable item in the assembly of the bearing, is maintained in a prime condition and that noise produced from metal/metal is not of a concern.
The Additional knowledge that metal mechanical artefacts are not depositing in the Bearing Housing and creating an abrasive at the critical interfaces, causing unwanted damages will no longer be a concern and unwanted energies produced from metal/metal contact or abrasives, are not being transferred to unwanted locations are also attractive conditions to have considered to be created.
There will also be one more condition created when a careful selection is made for a Sacrificial Part that is Non Metal, and a suitable environment is produced for their placement, which is the Co-Efficient of Friction for the overall assembly is going to be improved.
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If you want complicated, think of air bearings, and magnetic levitation....
🤔
New thread topic?
Ultra low friction bearings for turntables?
🤔
New thread topic?
Ultra low friction bearings for turntables?
"In a Steel Balls Static Electricity can manifest and transfer through the Steel Ball as a current.
When a lubricant is in use, that is Non Conductive, and the Hydrodynamic Condition is at its Poorest or Boundary Lubrication has manifested, the discharge of the electricity has the capacity to produce a Substantial Heat within the environment, which the heat can cause welding of the surfaces in close contact.
The impact of the Welding occurring is that 'pitting can be produced' on the metal surfaces."
I work as a service tech in the machine tool field and I have seen first hand what happens to precision bearings when current passes through them. That said, were talking very, very low currents when we deal with static on a TT. Not enough that it even comes up on my radar.
Where it becomes interesting is when someone is welding up a shaft and it's still in the lathe, I've seen the ground clamp on the bed of the machine. All welding current is passing through those precision spindle bearings at that point if no tailstock is being used. I've also had to replace those bearings a short time later. LOL
As far as running a hard material like a steel or ceramic on a bearing pad, it's advisable to use a soft material for the pad. My "go to" material is Delrin, very slippery, supports the weight without creating a big dimple and unlike a hard material helps to isolate any noise transfer.
BillWojo
When a lubricant is in use, that is Non Conductive, and the Hydrodynamic Condition is at its Poorest or Boundary Lubrication has manifested, the discharge of the electricity has the capacity to produce a Substantial Heat within the environment, which the heat can cause welding of the surfaces in close contact.
The impact of the Welding occurring is that 'pitting can be produced' on the metal surfaces."
I work as a service tech in the machine tool field and I have seen first hand what happens to precision bearings when current passes through them. That said, were talking very, very low currents when we deal with static on a TT. Not enough that it even comes up on my radar.
Where it becomes interesting is when someone is welding up a shaft and it's still in the lathe, I've seen the ground clamp on the bed of the machine. All welding current is passing through those precision spindle bearings at that point if no tailstock is being used. I've also had to replace those bearings a short time later. LOL
As far as running a hard material like a steel or ceramic on a bearing pad, it's advisable to use a soft material for the pad. My "go to" material is Delrin, very slippery, supports the weight without creating a big dimple and unlike a hard material helps to isolate any noise transfer.
BillWojo
There is a grade called 500CL in Delrin, the CL is for Chemically Lubricated, it has Teflon added.
Molybdenum Di sulfide is also used as an additive in Delrin and Nylon.
It is a good internal lubricant.
I think you can find rods of these materials.
If you need to, bear these in mind.
A hard grade of Teflon will also work as the bottom support of a TT.
And the precision bearings in lathes are Expensive!
People can be stupid at times.
Molybdenum Di sulfide is also used as an additive in Delrin and Nylon.
It is a good internal lubricant.
I think you can find rods of these materials.
If you need to, bear these in mind.
A hard grade of Teflon will also work as the bottom support of a TT.
And the precision bearings in lathes are Expensive!
People can be stupid at times.
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I tried to find disks of Delrin or Teflon to sit under the thrust bearing. Never found what I wanted, but it seemed like a good idea.
NAD5120 is running chromed steel on tungsten carbides discs...Dual, PE, Garrard and some other brands are running 5 steel balls on carbides too...while some japanese brands are running their direct drive motors chromed shafts on compressed air at the bottom sealed with teflon and oil (hardly touching it if the platter is overloaded) and on very fine fineshed brass tube walls as all the other brands do it laterally.Some japanese brands have such high rod and tube finish that air couldn't escape in 5 decades and that's verified.
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Magnetic levitation for turntables is a complete conceptual failure. While it can be made dynamically stable (non trivial task, though) the platter will always oscillate around the target position, much like a geostationary satellite oscillates around the orbital position. The result is wow and flutter, much worse than the worst bearing.
No way around, that's physics folks. It's called the Earnshaw's theorem.
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Nnnnope 🙂. The 20k+ Verdier TT is not with magnetic levitation, but with a magnetic cushion. The inverted 20mm diameter shaft has no bail or thrust plate; the spindle and underside of the planer are surrounded by two large ceramic ring magnets that repel each other, thus allowing the planer to float on a magnetic cushion. However, the sides of the bearing are in contact with the shaft, but the use of thick oil and a high standard of finish ensure minimal noise and friction. This makes this bearing having only one degree of freedom (Z Axis) which makes it good in terms of stability. It's like having a geostationary satellite anchored with a rope from Earth, of course it would be absolutely stable.
This works better and it's patented for more than 100 years and still offering the best thrust bearing running on air or oil...being the first to offer flotation to a 100 tons rotor in the 19th century...
https://en.m.wikipedia.org/wiki/Albert_Kingsbury
I don't know if you get it, but you can make also a linear tangential tonearm on that glass siringe if you make a rotating shaft or plunger ...
I don't know if you get it, but you can make also a linear tangential tonearm on that glass siringe if you make a rotating shaft or plunger ...
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