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In the Forum: Analog Playback
In the Thread: Copper Mat on a Micro Seiki Gun Metal Platter
Post Subject: Bearing issues.Posted by jam on: 11/7/2017
Hi Measet,
The original platter for the RX-5000 was gun metal which I replaced with a platter with a similar platter to Wellington's weighing about 50 lbs. , the other table came from Japan with a original stainless platter made by Micro Seiki (rare). The density of gun metal and steel are about the same. The main differences here are the resonant properties of the material used and total mass of the platter. I have found that Stainless steel sounds the best, followed by gun metal and aluminium being a distant third. I will post pictures of my platter if you wish.
The bearing has to be filled completely with oil. After you have cleaned the bearing and replaced any parts that have aged, insert the spindle into the bearing until it clears the bottom bushing and fill with oil from the top wile pushing the spindle up. When the area between the bushings is filled and the spindle is all the way up invert the bearing and fill the bottom with oil. Replace the bearing and thrust plate and screw the plate back to the bottom of the bearing, you will fell some resistance due to trapped air, this is taken care by holding the bearing horizontally with the setscrew in the middle of t facing up. Slowly release the setscrew to release any trapped air and re-tighten the set screw. Clean any spill with alcohol.
Your thrust plate was damaged by the defective ball. Newer ceramic materials are a lot tougher. There will always be a small dimple on the thrust plate which is normal.
I would advise always using a stainless thrust plate as harder materials such as ceramics and carbide will sometimes start breaking at the interface between the ball and thrust plate. Steel being a different slightly softer material prevents this. I have confirmed this with several carbide thrust plates I have tried. An all ceramic bearing might work with a light platter but no so with a Micro Seiki with a heavy platter.
About the question of oil viscosity, I prefer a lighter viscosity than originally used and due to faster startup and speed consistency, I feel you do not need lead or other questionable additives with today's synthetics.
I would like to know if hear any differences with the repaired bearing and if there are any changes in start up speed.
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