the thrust bearing which replaces the plastic pad used in the
stock item. Its a 7.5mm diameter steel shim and is 1.5mm thick. These
used for adjusting valve clearances on a motorcycle engine and are
easily obtainable. (lots of different thickness's) I've polished
one ready to use. The steel on steel contact with the
spindle, is only possible because its running in oil.
This modification is common on Thorens decks which have a similar
plastic thrust pad. From personal experience I can vouch that they do
run quieter this way, so why not on the Technics?