Turning Center Spindles Spindle Nose: A2-4 Outer Diameter: 150 mm Spindle Bore Dia. : 42 mm Max. Speed: 6,000 rpm Bearing Size: Ø70 Bearing Lubrication: Grease Kenturn has been designing, manufacturing, fabricating and marketing machine tool spindles of all kinds since 1983. The company prides itself on intensively studying spindle design and producing innovative technology.