Lcoblentz3 wrote:Well, so much for hoping for the best. The PEEK disc is dimpled and the bearing has a rough spot on it. I have new ceramic balls on the way. Now, what do I do with the PEEK disc? Certainly doesn’t appear to be easily removable.
Peer Gynt wrote:1. Does the Classic use a PEEK thrust plate?
Peer Gynt wrote:2. And how does a hard ball wear flat against PEEK?
No Lube? Transporting TT w/o removing platter? Dirt on ball?
Peer Gynt wrote:Just curious. My sense is that PEEK might reduce noise when in good condition, but it seems like life issues would trump the early service potential noise advantage.
Peer Gynt wrote:If the ball is really a ceramic, I guess wear debris would turn it into a mortar and pestle situation.
Peer Gynt wrote:How often does this bearing need to be replaced? And do current models have this characteristic too?
Brf wrote:PEEK and Stainless steel have a similar hardness, therefore, wear will manifest on both contact surfaces. The bearing has approximately 25,000 pounds per square inch of pressure, therefore, improper or inadequate lubrication, contamination, heat, etc will cause increased friction which will result in premature wear.
PEEK is easily machined, can take a high level polish, exhibits excellent wear resistance and has excellent damping properties which makes it an excellent choice for a bearing thrust plate. IMHO, due to the nature of the VPI bearing being inverted, the bearing needs more periodic cleaning and re-lubing than the specified once per year to ensure a long life.
.... the current bearing ball is Stainless Steel. Some users replace the SS ball with a Silicon Nitride (Si3N4) ball which is non-porous, non-magnetic, non corrosive and much harder than SS. The non-porous nature of Si3N4 allows them to be manufactured to a higher grade than SS which allows them to operate with less lubrication and friction. Since Si3N4 is much harder than PEEK, the PEEK thrust plate will wear more than the ball.
Most VPI tables use the same bearing material and configuration, therefore, wear should be consistent for all tables using the 20lb classic platter. Wear will also be dependent on usage and lubrication. To increase wear resistance, I've changed out the PEEK thrust pad for sapphire and the SS ball for Si3N4. My table's original bearing lasted 1.5 years, but my platter weighs around 30lbs.
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