Pros and Cons of Platter Mass

From my investigations undertaken of how a increased Platter Weight can impact on a TT that is not supplied with a Heavy Platter.                      I have learnt that the Thrust Pad can show signs of increased wear after a lesser period than anticipated, where inspection of the part has shown noticeable indentation occurring from the Point Loading.
There are harder Thrust Pad Materials that will alleviate this condition and offer improved performance and longevity of use.
There is also the condition that can be impacted on where a Spindle can have a eccentric rotation and the addition of Platter weight can cause an increase to the force from the Spindle when coming into contact with the Bearing Bush.
A Hydrodynamic condition for the lubrication may prevent the Spindle/Bush coming into contact. From my investigations of certain vintage TT's there is not much evidence to show the Bearing / Bush interface had successfully maintained a Hydrodynamic Interface, there was possibly not a design from the outset to produce the interface.

The reports of increasing the Mass/weight of the Platter are usually seen with a positive appraisal where there are perceptions that a improvement is present in relation to noise reduction.

I have not seen measurements that will show changes that are able to to support such modifications, the usual, is that there is a trend and the individuals carrying out the mod's are collective in their positive appraisal.   

Peripheral Rings and Puck Weights are a common used method, and when used are adding mass, where the Peripheral Ring has the added effect to increase inertia.
Each of these ancillaries when in use, add weight to the Platter and increase on the load being applied to the Spindle and Interfaces.  
I am not aware of any TT Producers putting forward disclaimers that advise against the use of such ancillaries. These ancillaries are commonly accepted as methods to be used to Clamp a LP to a Platter.

To date I have not seen any reports that suggest a detrimental outcome to a Bearing Assembly has occurred as a result of these ancillaries being used.  There may be others that know a different outcome.
   

The point made about Sacrificial Surfaces are important and within the Bearing Housing there are designs in place to address this.
The Spindle is usually designed to be the part that has the Hardest Surface and in a good design will usually be produced with a Case Hardened Surface.  
Bush Materials are selected that are produced to have lessened surface hardness than the Spindle.
A vintage TT that has not had a life of function with a Spindle / Bush Interface where a Hydrodynamic condition is present is at risk of having produced a wear to the Bush Material. When the Bush is produced from a Metal, the risk also becomes that abrasives may be in the Bearing Housing and having an unwanted impact on the important parts and interface surfaces. The Wear can impact on other important areas of function, especially increasing the likelihood that an eccentric rotation will develop.

A Spindle does not usually interface directly with a Thrust Pad, there is a intermediary part used that is Sacrificial, in many cases this part is a Metal Ball, that can be found to be a interference fit into the base of the Spindle or in other cases a fully exposed ball that is a standalone part.
These Balls have been witnessed scored on the surface as a result of being in an environment that is abrasive. 

The modern designs for the sacrificial parts used at the interfaces are more commonly moving away from the use of Metal and are leaning towards the use of Thermoplastics as a Bush and Thrust Pad, and the Metal Ball is more commonly seen removed from a design and exchanged for a different material that has formed the ball.

In relation to vintage TT's with long periods of use behind them where a bearing housing is using Metal Sacrificial Parts, it is difficult to condone that a application of a new lubrication only is the required treatment to produce a environment for the Spindle to function without impediment.

There are many grades of Thermoplastics with different properties for the resilience to wear.
POM and PEEK are two examples and the PEEK is common choice to be used when a Platter is going to be above a certain weight.
It does not have a property that would wear a correctly selected interface ball or will it cause damage to the Spindle.
There are more modern Thermoplastics that can be selected with properties that are further suited to the use within a bearing housing.