SKFNN3005K/SPDouble Row Cylindrical Roller Bearing 25x47x16 mm Tapered 1:12 Bore Super-Precision SP Non-Locating

Product Description

What this part is

A double-row cylindrical roller bearing with a tapered bore, in the SKF super-precision class. Bore 25 mm, outside diameter 47 mm, width 16 mm.

Decoding the designation

NN — double-row cylindrical roller design, with the rollers guided by integral ribs.
3005 — the size: 25 mm bore, 47 mm outside diameter, 16 mm width.
K — tapered bore, 1:12 taper.
SP — SKF super-precision class, with tighter bore, outside diameter and running accuracy tolerances than a standard bearing.

What these specs mean in practice

Two rows of cylindrical rollers give a very high radial load capacity and high radial stiffness in a short axial length, which is why this design sits at the front of machine tool spindles. The bearing is non-locating: it carries radial load only and allows the shaft to move axially relative to the housing, so axial location comes from a separate thrust or angular contact bearing in the arrangement.

Fitting notes

The 1:12 tapered bore of an NN cylindrical bearing seats directly on a tapered spindle journal — no adapter sleeve is part of this design, unlike a spherical roller bearing carrying the same K suffix. Radial internal clearance is set by how far the inner ring is drawn up the taper, usually against a lock nut, so the drive-up distance is the adjustment.

Interchange guidance

The straight-bore counterpart is the NN3005, dimensionally identical apart from the cylindrical bore. An NNU3005 is a different internal design with the roller rows guided by the outer ring, and single-row NU, NJ and NUP bearings of similar envelope differ in both row count and axial behaviour — all related sizes rather than interchanges.