The Ball Bearing Preload Disc Spring is one of the type of Disc Springs that Caleb Components offers.
These Discs are specifically produced to take up play due to manufacturing tolerances. Each Disc is made to suit a ball-bearing code e.g. 6001, 6002 etc. to ensure that parts match the relevant ball-bearing.
These are now available to purchase online!
https://springfasteners.co.uk/product-category/disc-springs/ball-bearing-pre-load-disc-springs/