I have recently bought a Dore Westbury milling machine. It vibrated at the spindle and I assumed it was out of balance and put the gearbox onto a mandrel in the lathe to check. It was in balance so unfastened four screws in top plate of spindle to check bearing as there was some movement at the top of the spindle. When I removed square plate it appeared to have been machined to house a ball bearing but did not have one in place. Having no drawings to check on has anyone got the necessary information please. The top plate is bored to two and one eighth diameter by seven sixteenth deep.

Thank you gentlemen for you answers to my querie. I have to put my hand up and admit the true reason for the vibration was the circular nut to holding the bearings it place had, despite the grub screw, loosened off. I had started to remove the circular nut to inspect and taking an Allen key to the grub screw was ashamed to find it was not tight.😩 I screwed the nut up again to the bearing, locked up the grub screw and milling machine had lost its rattle.😁