Classic Platter Bearing Cup removal. How I did it.

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Vic

A new cartridge replacement on my Well Tempered turntable seemed to shed a brighter light on a channel imbalance. On closer inspection the tonearm silicon had become too thick and the Acrylic platter was no longer level with the plinth nor was it perpendicular to the tonearm pillar. Adjusting the platter spindle seemed easily adjustable using the nylon grub screws within the spindles high tolerance well anodized two piece aluminum bearing assembly.

To adjust the nylon grub screws within the bearings inner cup it must first be extracted from the outer cup. After removing the platter and spindle one might be able to simply stick a finger in the bearing assembly and lift out the inner bearing. With a combination of shear suction and years of time mine wouldn't budge.

With the platter and spindle already removed I disconnected and removed the cartridge the tonearm and drained the old tonearm silicon. I stuffed paper towels in the bearing to soak up the bulk of its silicon.

I was unable to push the bearing assembly out from the underside of the plinth by hand. I cut a piece of inner tube rubber and two sided taped it to the bottom of the bearing. Using the bottom of an 1-1/4" socket with a short extension in the hex side of the socket to carefully drift the assembly out from the plinth.

Wash out the bearing with mild soap and warm water.
Fill a deep saucepan with enough water to reach the underside of the bearings flange.
Dry the bearing and placed it in the freezer for at least two hours or more.
Bring the water to full boil and remove the saucepan from the burner.
Using a tongs place the frozen bearing in the hot water for 10-30 seconds then remove the bearing into a dish towel and stick your finger in the still cold inner bearing, twist and pull on the inner cup.
Continue to repeat the freezing and heat until the upper two nylon grub screws are accessible (about 3/4") using a 3/16" or 5mm allen wrench.

Care must be taken not to strip the nylon sockets as the nylon grub screws may be just as stuck as the bearing.
I applied a plastic compatible gear oil on the threads of the grub screws and placed the bearing grub screws down, back in the freezer so the oil doesn't flow off the threads.
Remove and carefully work the screws loose with short back and forth movement. Repeat the freezing as needed.   



The inner portion of the bearing assemble extracted about 3/4" to access the upper grub screws.





« Last Edit: 18 Feb 2018, 05:27 am by Vic »

ulysses

  • Jr. Member
  • Posts: 57
Re: Classic Platter Bearing Cup removal. How I did it.
« Reply #1 on: 20 Feb 2018, 02:26 am »
Vic,

As the original owner of a 30-year old original Well Tempered table and arm still in daily use, I found your post to be fascinating. Although the platter on my table is perfectly horizontal to the plinth, there's a decent possibility that I might find myself making the same repair/adjustment to my table someday. I'm 72 years old now and it looks like I'll probably keep my incredible sounding (and extensively modified and precisely set up) Well Tempered until I'm carried off to the assisted living home or the funeral home.

I've got a question for you: once you had the platter bearing well removed from the plinth and the top two nylon grub screws exposed, when you adjusted the screws how did you determine that the platter would be exactly horizontal to the plinth? I can't imagine that it was trial and error. Please explain.

As I side note, I should say that I'm still using the original fluids in both the tonearm and platter bearings. But after reading your post, I'll check to see if they've thickened over the decades.

Thank you!

Phil

Vic

Re: Classic Platter Bearing Cup removal. How I did it.
« Reply #2 on: 20 Feb 2018, 10:17 am »
Phil,

I'm sure the manufacture had a much simpler way of doing these setup procedures. 

Once the spindle well was removed from the plinth I cleaned out its hole so the well could just barely be removed by hand.
Place the plinth on a level surface and check that the tonearm pillar is still square to the level plinth surface.
Insert the dry well in the plinth and index the dot on the outer cup facing the motor.
Raise the motor on blocks to match the hight of the extracted inner bearing, spindle, and platter.
Insert the dry spindle in the bearing and place the platter upside down on the spindle, and belt it to the motor. 
Run the motor for a few revolutions to settle it in.
Read the level on the belt side of the platter on the radius line with one of the grub screws, approximately 2 and 4 o'clock.
Adjust the grub screws accordingly.


I wouldn't imagine this adjustment ever need be done even under long term normal use. My unit was purchased in great disrepair and neglect. Its upper grub screws may have worn due to the lack of lubricant or the sever impact that bent the tonearm.

My tonearm seemed slow to settle in and causing unusual issues. Replacing the silicon was the only way I realized it it was too thick and/or full of dust, whatever.
The fluid in the spindle well was below the upper nylon grub screws and most likely caused their wear creating the leveling issue.
« Last Edit: 20 Feb 2018, 07:38 pm by Vic »

ulysses

  • Jr. Member
  • Posts: 57
Re: Classic Platter Bearing Cup removal. How I did it.
« Reply #3 on: 22 Feb 2018, 10:58 pm »
Vic,

Thanks for your detailed reply. I'm saving your posts in case my original Well Tempered ever has platter bearing well problems.

Phil