Essential job if damage to the taper socket is to be avoided when inserting taper shanks. They will squirt cutting oil where you want it when drilling deep holes, and with a larger bore needle you can use them for grease too - keeps messy black molybdenum grease off your hands. Replaced easily when it gets worn.
Picture shows syringe oilers and blue applicator.
I've got a spherical turning attachment, but even so I looked at the possibility of using ball bearings to make ball handles. Problem is drilling the darn things. Grinding flats on them to get beneath the hard surface doesn't work, neither will a carbide drill put a hole in one. So, anneal them first. Picture shows ball bearing drilled and tapped 2 b.a.