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Platter thrust plate and bearing replacement - Sapphire and Si3N4
#21
Well done!

"With the ball removed I could see the stuff used to hold it in place... "

Any idea what the stuff was?
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#22
(05-15-2022, 08:39 PM)seamonster Wrote: Well done!

"With the ball removed I could see the stuff used to hold it in place... "

Any idea what the stuff was?

Thank you! It was some kind of adhesive, but not sure if it was clear epoxy or what...
Whoa listen to the music...

Wachuko
VPI Scoutmaster Refurbish, Prime Signature Motor (300 rpm), Prime Aluminum (20 lbs) Platter and Bearing, Delrin Record Clamp, JMW 9 3D Arm with Sumiko Blue Point No.2, Upgraded Classic Feet, Periphery Ring Clamp
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#23
Thanks, wachuko. I should also have asked what you used to remove it. Acetone?
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#24
Good job! Remember to adjust arm height, VTF/VTA, etc.
[Image: full]
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#25
(05-15-2022, 10:45 PM)seamonster Wrote: Thanks, wachuko. I should also have asked what you used to remove it. Acetone?

Just a plastic scraper/pick I have... it came off easily...  then some 3M fine pad to clean whatever was left.  Acetone at the end to remove anything that could be left... but the bulk of it was with that plastic pick...

(05-15-2022, 11:03 PM)edwyun Wrote: Good job!  Remember to adjust arm height, VTF/VTA, etc.

Oh... that is right.  To account for the thickness of the thrust plate.  I will do that.  Thank you for calling that out.  Cool
Whoa listen to the music...

Wachuko
VPI Scoutmaster Refurbish, Prime Signature Motor (300 rpm), Prime Aluminum (20 lbs) Platter and Bearing, Delrin Record Clamp, JMW 9 3D Arm with Sumiko Blue Point No.2, Upgraded Classic Feet, Periphery Ring Clamp
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#26
Thanks, wachuko -
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#27
Maybe a topic for another thread, but let me ask here first.

Stock setup is steel ball against a brass surface...

This upgrade is a Si3N4 Ceramic ball against a sapphire surface...

What about adding a Delrin plate between the sapphire thrust plate and the brass?

So you have the platter with the brass insert -> Delrin disc-> Sapphire thrust plate/disc -> a Si3N4 Ceramic ball

Delrin plate could be made to accommodate the undersized sapphire disc. So nothing from the sapphire disc touches the brass...

Is there any sound benefits to this approach? So the Delrin acts as an impedance to stop any vibration (noise) from transferring from the platter to the chassis. The sapphire disc still rests on top of the ceramic ball, but the disc is isolated from the brass... makes sense?

Not my idea/suggestion... something I read on another forum and wanted to get your ideas/comments.
Whoa listen to the music...

Wachuko
VPI Scoutmaster Refurbish, Prime Signature Motor (300 rpm), Prime Aluminum (20 lbs) Platter and Bearing, Delrin Record Clamp, JMW 9 3D Arm with Sumiko Blue Point No.2, Upgraded Classic Feet, Periphery Ring Clamp
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#28
The thrust plate used in the Prime/Classic platter is not made from brass but made from Polyether ether ketone (PEEK) which is a thermoplastic polymer. PEEK has excellent damping properties and is often used in bearing applications.

The older VPI oil bath bearings utilized a brass plug which a tungsten thrust plate recessed into the brass top face. The brass plug was quite substantial and did an excellent job of draining unwanted resonance away from the platter interface. Also, the tungsten thrust plate and bearing ball was immersed in oil which provided another layer damping.

Now that we have established that the current thrust plate is PEEK and not brass, adding a layer delrin would IMHO provide no benefit and perhaps a step backwards unless one decides to mechanically couple the materials together to act as a single unit.

Btw, nice job on the bearing upgrade.
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#29
(05-17-2022, 07:18 PM)Brf Wrote: The thrust plate used in the Prime/Classic platter is not made from brass but made from Polyether ether ketone (PEEK) which is a thermoplastic polymer.  PEEK has excellent damping properties and is often used in bearing applications.

The older VPI oil bath bearings utilized a brass plug which a tungsten thrust plate recessed into the brass top face.  The brass plug was quite substantial and did an excellent job of draining unwanted resonance away from the platter interface.  Also, the tungsten thrust plate and bearing ball was immersed in oil which provided another layer damping. 

Now that we have established that the current thrust plate is PEEK and not brass, adding a layer delrin would IMHO provide no benefit and perhaps a step backwards unless one decides to mechanically couple the materials together to act as a single unit.

Btw, nice job on the bearing upgrade.

Ohhh great to know!  Since the area around it was brass, I thought the bottom of it was brass as well.  So there is an insert of PEEK inside that brass bushing.  I did not know that.

Thank you for the info!!!
Whoa listen to the music...

Wachuko
VPI Scoutmaster Refurbish, Prime Signature Motor (300 rpm), Prime Aluminum (20 lbs) Platter and Bearing, Delrin Record Clamp, JMW 9 3D Arm with Sumiko Blue Point No.2, Upgraded Classic Feet, Periphery Ring Clamp
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#30
Here is a picture of the PEEK thrust plate. 

   
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