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Platter thrust plate and bearing replacement - Sapphire and Si3N4
#1
Question 
Hello!

Sad  I had all this bookmarked and lost it when the site was changed: vpiforum.com • View topic - Magnetic Platter bearing replacement - Sapphire and Si3N4

  1. Anyone has information on the specifications for the sapphire thrust plate?  And where to source it from?
  2. Anyone has information on the specifications for the silicone nitrite (Si3N4) ceramic bearing ball? And where to source it from?

Some photos I had from a fellow that provides replacement services.  Photos are with a ceramic ball replacement.

Sapphire trust plate:

[Image: file.php?id=117281&t=1]

Ceramic ball replacement on the right and stock steel ball on the left

[Image: file.php?id=117280&t=1]


But I want to tackle this myself, and want to use the Si3N4 bearing ball as was recommended in that thread.   It was mentioned, if I remember correctly, that silicone nitrite (Si3N4) ceramic ball was better than going with some other kind of ceramic ball.  I just need a source for the parts or the specifications so I can search for suppliers of these items...  

This is for a VPI Scoutmaster Refurbish with Prime Signature Motor (300 rpm) and Prime Aluminum (20 lbs) Platter and Bearing
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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#2
I was hoping to not have to remove the platter to take measurements... Wanted to be able to buy the parts needed before taking anything apart. Looks like I will have to remove the platter to measure the diameter for the thrust plate.

So far, I think I have found the size for the ball... from the search hits on other sites, looks like it is 1/4" ball... McMaster carries this: https://www.mcmaster.com/9576K34/

[Image: file.php?id=117288]

But I lucked out on the size of the thrust plate... Hopefully, someone here will chime in.
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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#3
Wachuko, the only person I know about selling sapphire thrust plates is Steve Leung at VAS Audio. I do not have the specifics on the type of ceramic ball he uses, but he is friendly and can answer any questions. Good luck!

Steve Leung - VAS Audio

77 Cliffwood Ave, Suite 3B
Cliffwood, NJ 07721
USA

vasaudio@comcast.net
+1-732-888-3288
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#4
Thank you! I will reach out to him and see if he is willing to share the diameter or if he can just sell me the sapphire thrust plate. I ordered the bearing ball from McMaster a few minutes ago...

So Steve is the one that provides the complete service! I found his eBay posting:

https://www.ebay.com/itm/393535972604?ha...SwV71hl9IG

I do hope he can sell me the sapphire plate... I want to change this myself...

Turns out, those were his photos that I found in my search.
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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#5
Wachuko, if you still want to try DIY, the sapphire plates can be had from Esslinger (but you need to know the thickness and diameter), and the bearings from Boca Bearings.
VPI Avenger Direct (Serial #0001 Big Grin ), Fatboy gimbal 12”, various carts, Von Schweikert E SE, Pass XP20, Pass X260.8 monoblocks, PS Audio PST and DS DAC, Sonore ultraRendu, Matrix X-SPDIF2
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#6
(05-10-2022, 09:40 PM)tony22 Wrote: Wachuko, if you still want to try DIY, the sapphire plates can be had from Esslinger (but you need to know the thickness and diameter), and the bearings from Boca Bearings.

Thanks!!!

https://www.esslinger.com/ 

Cool!  Documenting here for others as well.  But Steve got back to me and is willing to sell me two.  I will just order from him and avoid trying to figure out all that.
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
Reply
#7
(05-10-2022, 08:23 PM)wachuko Wrote: I was hoping to not have to remove the platter to take measurements... Wanted to be able to buy the parts needed before taking anything apart. Looks like I will have to remove the platter to measure the diameter for the thrust plate.

So far, I think I have found the size for the ball... from the search hits on other sites, looks like it is 1/4" ball... McMaster carries this: https://www.mcmaster.com/9576K34/

[Image: file.php?id=117288]

But I lucked out on the size of the thrust plate... Hopefully, someone here will chime in.

If you have a Prime 20lb platter and bearing I highly doubt that the ball bearing is 1/4”. Take the platter off and take some measurements.

IIRC, the ball bearing is 3/8”
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#8
Watching thread.
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#9
(05-10-2022, 10:15 PM)Brf Wrote: If you have a Prime 20lb platter and bearing I highly doubt that the ball bearing is 1/4”.  Take the platter off and take some measurements.  IIRC, the ball bearing is 3/8”

I ended up removing the platter as Steve also needed confirmation on the diameter of the hole in the platter...

Sharing photos:

I can't remember what grease I used when new... this was just short of two years ago and the turntable has not had that much use.  Still, I need to remember to do this more often...

Platter removed.  Quick photos of old grease...

[Image: file.php?id=117312&t=1]

[Image: file.php?id=117316&t=1]

[Image: file.php?id=117313&t=1]

Shaft is 1/2" 

[Image: file.php?id=117314&t=1]

Bearing ball is actually 5/16"... I need to order the correct one... I will have two 1/4" bearing balls to hang in the wall of shame... great conversation pieces   Shy

[Image: file.php?id=117315&t=1]

[Image: file.php?id=117332&t=1]

[Image: file.php?id=117331&t=1]

Cleaned... 

[Image: file.php?id=117317&t=1]

Went ahead and lubed the bearing ball and installed the platter in place... 

Ordered the correct bearing ball this time... in 5/16"

[Image: file.php?id=117333]

Now to wait for the parts to arrive...
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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#10
I'm not questioning your measurement accuracy, but when I did a couple of Prime bearing replacements just before Xmas, both spindles had a 3/8' ball.  Perhaps VPI uses more than one size?  Since replacement balls are very inexpensive, I would order both sizes just to be on the safe side

I have attached a picture of the old ball with a measurement and a copy of the replacement Si3N4 ball.


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