Just updating my previous drawings since I was able to completely undo it my tonearm pillar (confirming bottom cup assembly).
unfortunately, it is not possible to edit previous posts ro replace former drawings.
In a tentative answer to Donic questions, I have no knowledge of the effective difference between different bearings in a tonearm, I am just trying to replace faulty ones (no way I can clean the original ones completely).
The stress put on the ball bearings in a tonearm, extremely slow and regular micro movment across a 70° max angle
, is completely different from what they are made for; these bearings are designed to spin at relatively very high speeds.
I've just received from BOCA Bearings 2 SMR689 #5 Radial Bearings 9 x 17 x 4 Millimeters treated with UDL lube.
BOCA has been very responsive and cooperative... and very quick shipping...
I ordered those on the following reasonning:
- ABEC 5 (#5) should correspond to better precision and efficiency,
- UDL treatment, to avoid any oiling,
- open since the original ones are open and the pillar assembly itself makes an enclosure.
It seems clear that I will need to run them in. I'll do that on a makeshift (electric drill) device runing them hight spped for few hours turning both ways.
When my tone arm will be in operation again, I will report...