NN3017K is double row precision cylindrical roller bearing with 1:12 tapered inner bore, dimension 85×130×34mm. Double symmetric roller rows deliver ultra-high radial rigidity, zero axial displacement during rotation. K suffix represents tapered bore to fit adapter sleeve, easy clearance adjustment for spindle preload. Separable outer ring simplifies installation, superfinished raceway ensures low vibration and high-speed stable running. Widely used in CNC lathe spindles, surface grinders, machining center main shafts and precision high-speed rotary equipment.