Magnetic Platter bearing replacement - Sapphire and Si3N4

Magnetic Platter bearing replacement - Sapphire and Si3N4

Postby Brf » Mon Dec 11, 2017 9:36 pm

Snow filled day equals maintenance time, so I decided to upgrade the bearing assemply on my VPI magnetic drive platter bearing. One of the real benefits of the magnetic drive platter is it’s ease of service.

I took the mag drive platter assemply apart and noticed a small wear dimple on the main oil both ball bearing and a slight wear indentation on the PEEK thrust plate. The inverted bearing which supports the main platter shows absolutely no sign of wear. This was to be expected since the main inverted bearing does not rotate freely when the total platter assembly spins.

I have a small arsenal of bearing bits and parts which I have collected over the years. I decided to replace the stainless steel ball bearing on the oil bath bearing shaft with a military grade 3 silicon nitride (Si3NI4) ceramic ball bearing. The grade 3 bearing is the roundest and smoothest bearing made in the world and is much harder than stainless steel. I have previously played with ruby ball bearings and although they are very hard and demonstrate excellent wear resistance, they can’t be polished as fine as the silicon nitride.

Thrust plate material was an easy decision. Although I like the natural damping properties of PEEK, it is subject to wear over a period of time as evident by the wear in my 1.5 year old bearing. I wanted something that is extremely wear resistant I.e. very hard and can take a high level of polish. I decided on a sapphire crystal bonded to PEEK substrate using an ultra violet activated glue. The PEEK substrate provides the sapphire the needed damping and supports the realitively brittle sapphire.

It took less than an hour to perform the bearing swap and should be maintenance free for a very long time, possibly a lifetime.

Lubrication used was Mobile One 30 weight synthetic oil.

I gently put the drive platter into the oil bath bearing well being very careful not to drop it on the delicate sapphire. I lubed up the inverted bearing using a dab of lithium synthetic grease impregnated with PTFE and set my SDS on 45 rpm and let the bearing run in for 6 hours.

The end result is an Absolutely dead quiet bearing (I use a stethoscope) which spins freely with little resistance. I am still evaluating the sonic improvement, but there is an improvement.

Highly recommended upgrade. I have posted a few pictures of the process.
Attachments
41D8C19F-06C0-4D29-B003-CA265D02C262.jpeg
41D8C19F-06C0-4D29-B003-CA265D02C262.jpeg (335.86 KiB) Viewed 1780 times
377ED895-E5B4-4AF3-8FDB-280FD17FD874.jpeg
377ED895-E5B4-4AF3-8FDB-280FD17FD874.jpeg (289.68 KiB) Viewed 1780 times
2CA46C5A-2705-4C9A-BDDD-8B64666D01A4.jpeg
2CA46C5A-2705-4C9A-BDDD-8B64666D01A4.jpeg (375.17 KiB) Viewed 1780 times
207B95BB-A1D3-4A01-BAB1-81932658B5AB.jpeg
207B95BB-A1D3-4A01-BAB1-81932658B5AB.jpeg (451.15 KiB) Viewed 1780 times
6437E96A-0F30-46CE-AB63-51D7EBE8BA61.jpeg
6437E96A-0F30-46CE-AB63-51D7EBE8BA61.jpeg (504.18 KiB) Viewed 1780 times
5D8ACA07-F710-476E-B964-82730A1E4D54.jpeg
5D8ACA07-F710-476E-B964-82730A1E4D54.jpeg (590.71 KiB) Viewed 1780 times
9F18DDB2-B928-4137-A4F6-D8FA4AEABA8D.jpeg
9F18DDB2-B928-4137-A4F6-D8FA4AEABA8D.jpeg (615.65 KiB) Viewed 1780 times
User avatar
Brf
Site Admin
 
Posts: 3605
Joined: Tue Aug 26, 2014 9:23 am

Re: Magnetic Platter bearing replacement - Sapphire and Si3N

Postby bryanjan » Mon Dec 11, 2017 11:20 pm

Good job BrF.

I did the same ceramic ball bearing and PEEK thrust plate replacement few months ago.

May I know where can I get the sapphire crystal?

Bryan
bryanjan
Member
 
Posts: 51
Joined: Mon Mar 07, 2016 5:45 am

Re: Magnetic Platter bearing replacement - Sapphire and Si3N

Postby JimmyL » Tue Dec 12, 2017 1:50 am

That is quite a rig you have there Brf! Very impressive.
VPI HW19 mod’ed MK3 w/JMW10.5i, VAS HW Nova Special 0.4mV, Musical Paradise MP501 V2 Integrated Tube amp, MP Tube Phono Pre, MP Tube D1 DAC, Harbeth P3esr’s
JimmyL
Member
 
Posts: 83
Joined: Thu Nov 09, 2017 1:55 pm

Re: Magnetic Platter bearing replacement - Sapphire and Si3N

Postby DrumTemp » Wed Dec 13, 2017 12:33 pm

Please enlighten me: You use both grease & oil? I've poured over the Avenger manual and all I see mention of is re-greasing the bearing once a year; nothing about oil. Also, your original bearing lasted 1 1/2 years; is that about normal?
Avenger Reference, Graham Phantom III, Benz Micro LP S, AI Mod 3B, Pass Labs X250.8, Vandersteen Quatro Wood CT
DrumTemp
Member
 
Posts: 67
Joined: Thu Nov 24, 2016 12:48 pm

Re: Magnetic Platter bearing replacement - Sapphire and Si3N

Postby Letsmakeadeal » Wed Dec 13, 2017 1:31 pm

DrumTemp wrote:Please enlighten me: You use both grease & oil? I've poured over the Avenger manual and all I see mention of is re-greasing the bearing once a year; nothing about oil. Also, your original bearing lasted 1 1/2 years; is that about normal?


Hey Brent

Like DrumTemp, I don't recall any oil in our set up.

Would you please tell us more about the use of oil in the lower bearing? How much oil is used?

Would you please give links on where to purchase the upgrade parts? Ceramic bearing, Sapphire plate

Description on how to remove the thrust bearing, etc.

Did you polish your platter?

Thanks
User avatar
Letsmakeadeal
Senior Member
 
Posts: 541
Joined: Fri Aug 29, 2014 3:42 pm
Location: Texas

Re: Magnetic Platter bearing replacement - Sapphire and Si3N

Postby Gary1955 » Wed Dec 13, 2017 1:55 pm

Wow Brf, this is something which I find very compelling to do on my HR-X magnetic drive. I have never removed a thrust plate or the bearing before and wonder how challenging it is to do. I wish VPI would offer this as an upgrade or standard on their higher end tables as much longer life and quieter running are both something that I'm willing to pay extra for now! Thanks for sharing.
VPI HR-X rim drive w/magnetic drive platter, 3D Ref. 12" tonearm, Lyra Titan-i cartridge, Graham Slee Reflex M & Elevator, tri-amped horn system w/electronic crossover, PrimaLuna Dialogue Premium preamp.
Gary1955
Senior Member
 
Posts: 516
Joined: Sun Sep 21, 2014 10:45 pm

Re: Magnetic Platter bearing replacement - Sapphire and Si3N

Postby Brf » Wed Dec 13, 2017 8:40 pm

DrumTemp wrote:Please enlighten me: You use both grease & oil? I've poured over the Avenger manual and all I see mention of is re-greasing the bearing once a year; nothing about oil. Also, your original bearing lasted 1 1/2 years; is that about normal?


The magnetic drive platter "assembly" consist of two platters; a drive platter and a slave platter. The drive platter is supported by an oil bath bearing which is housed in the plinth. This bearing is best lubricated with 30w synthetic oil. The slave platter is supported by an inverted bearing (very similar to that of the Classic/Prime platter). Due top the fact that the bearing is inverted, lithium grease is used for lubrication as 30w oil would simply flow away from the bearing.
User avatar
Brf
Site Admin
 
Posts: 3605
Joined: Tue Aug 26, 2014 9:23 am

Re: Magnetic Platter bearing replacement - Sapphire and Si3N

Postby Brf » Wed Dec 13, 2017 9:04 pm

Letsmakeadeal wrote:Like DrumTemp, I don't recall any oil in our set up.

Would you please tell us more about the use of oil in the lower bearing? How much oil is used?


See above post. The lower oil bath bearing should be lubricated with 1ml of 30 weight synthetic oil.
Letsmakeadeal wrote:Would you please give links on where to purchase the upgrade parts? Ceramic bearing, Sapphire plate


You can purchase online grade 5 3/8" ceramic Si3N4 ball bearings from Boca Bearing. Grade 3 are special order. As for the sapphire thrust plate, my good friend is the CFO for Rolex and he had one of his watchmakers make me a 1mm x 15.8mm round sapphire disk. You can order sapphire round disks from most watch supply houses. Typically, 16mm is the smallest diameter, therefore, you will need to find a supplier willing to custom cut one for you.

Letsmakeadeal wrote:Description on how to remove the thrust bearing, etc.


I used a micro torch (see picture below) to heat the ball bearing. The heat causes the ball to expand which causes a shear force between the ball bearing and the bearing shaft which breaks the super glue.

The thurst plate is simple held in place (friction fit) in the removalable stainless steel thrust plate plug/cap as originally pictured beside the PEEK thrust plate above.
Letsmakeadeal wrote:
Did you polish your platter?

Yup, used Mothers Aluminum and Mag polish
Attachments
Micro torch.JPG
Micro torch.JPG (61.8 KiB) Viewed 1631 times
User avatar
Brf
Site Admin
 
Posts: 3605
Joined: Tue Aug 26, 2014 9:23 am

Re: Magnetic Platter bearing replacement - Sapphire and Si3N

Postby Brf » Wed Dec 13, 2017 9:10 pm

Gary1955 wrote:Wow Brf, this is something which I find very compelling to do on my HR-X magnetic drive. I have never removed a thrust plate or the bearing before and wonder how challenging it is to do. I wish VPI would offer this as an upgrade or standard on their higher end tables as much longer life and quieter running are both something that I'm willing to pay extra for now! Thanks for sharing.


It's not very challenging, took me less than 45 minutes. Perhaps in the future , VPI will offer upgrade bearing options, but that would be contingent on their belief that a bearing upgrade is needed. I am always pushing the performance on all my tables.

Up next, a sapphire skate plate for my dual pivot.
User avatar
Brf
Site Admin
 
Posts: 3605
Joined: Tue Aug 26, 2014 9:23 am

Re: Magnetic Platter bearing replacement - Sapphire and Si3N

Postby DrumTemp » Wed Dec 13, 2017 9:49 pm

Thank-you Brf for the info!
If I may ask another question: How exactly do you separate the two platters? When I assembled my Avenger I lifted the two platters together as one, and (carefully) set them down on the base and into the bearing shaft. My Avenger is less than a year old, but I think I've only lubed the oil bath well thus far. When I cleaned the oil bath well, my Q-tip showed grease.
Avenger Reference, Graham Phantom III, Benz Micro LP S, AI Mod 3B, Pass Labs X250.8, Vandersteen Quatro Wood CT
DrumTemp
Member
 
Posts: 67
Joined: Thu Nov 24, 2016 12:48 pm

Next

Return to Support Forum

Who is online

Users browsing this forum: No registered users and 3 guests

cron

x