FAGNN3011KMSP5Double-Row Cylindrical Roller Bearing 55 x 90 x 26 mm, 1:12 Tapered Bore, Machined Brass Cage, Lube Groove and Three Holes, Super-Precision SP

Product Description

What this part is

A FAG NN3011-AS-K-M-SP double-row cylindrical roller bearing, 55 mm bore x 90 mm outside diameter x 26 mm wide, with a 1:12 tapered bore, a machined brass cage, super-precision tolerances and an annular lubrication groove with three radial feed holes in the outer ring. Two rows of rollers in a 17.5 mm cross-section carry 72 kN dynamic load at up to 9 000 rpm. This is a machine-tool spindle bearing.

Decoding the designation

NN — double row, three ribs on the inner ring, ribless outer ring. Radial load, with axial displacement accommodated in both directions.
30 — ISO dimension series 30.
11 — 55 mm bore.
AS — FAG code for an annular lubrication groove and three radial holes in the outer ring, the feature other makers designate W33.
K — tapered bore, taper 1:12.
M — machined brass cage, roller-centred.
SP — FAG super-precision: ISO tolerance class 5 dimensional accuracy with class 4 running accuracy, equivalent to the P5 marking that appears on some cartons.

What these specs mean in practice

The 1:12 tapered bore is what distinguishes this from a straight-bore NN3011. On a cylindrical NN the tapered inner ring seats directly on a tapered spindle journal, with no adapter sleeve in the assembly. Drawing the ring up the taper expands it a measured amount, so radial clearance — or a light preload — is set by axial travel rather than by ordering a clearance class. A spindle builder reaches a repeatable running clearance that way.

The AS lubrication feature feeds oil or grease into the bearing through the housing rather than past the ring faces, which is what allows the 9 000 rpm limiting speed alongside roller-bearing load capacity. The ribless outer ring makes this the floating position: it slides in the housing bore as the shaft grows with temperature, and axial location comes from a thrust or angular-contact bearing elsewhere in the shaft.

Published ratings and mounting data

Bore d: 55 mm — Outside diameter D: 90 mm — Width B: 26 mm
Basic dynamic load rating Cr: 72 kN
Fatigue limit load Cu: 15.6 kN
Limiting speed: 9 000 rpm
Rows: 2 — rolling element: cylindrical roller — open, no seals or shields
Bore taper 1:12 — cage: machined brass, roller-centred
Outer ring: annular lubrication groove with three radial holes (FAG AS)
Tolerance class: SP — ISO class 5 dimensional, class 4 running accuracy
Operating temperature range: −30 °C to +150 °C
Material: through-hardened bearing steel
EAN: 4012801017213

Quantity and configuration

Sold as 1 Pc — one complete bearing: the ribless outer ring with its lubrication groove, and the tapered-bore inner ring carrying both roller rows and both brass cages. The bearing separates into those two assemblies, which are a matched pair.

Fitting notes

Mounting is cold and clean, onto a tapered journal ground to the matching 1:12 taper. Bore expansion is measured at each increment of drive-up and radial clearance checked between increments until the target figure is reached. The three lubrication holes in the outer ring line up with the housing feed port, and the outer ring stays free to slide axially in its bore. The taper surface is a precision reference face and stays free of nicks, since a high spot there reads as spindle runout for the life of the machine.

Interchange guidance

Same-specification equivalents at 55 x 90 x 26 mm, 1:12 tapered bore, machined brass cage, lubrication groove and holes: SKF NN 3011 KM/SPW33, NSK NN3011KME4, NTN NN3011KC1NAP4, Rollway NN3011KMW33. Related sizes, not substitutes: the straight-bore NN3011-AS-M-SP seats on a cylindrical journal and sets clearance by class rather than by drive-up; NNU4911 in a comparable envelope carries its ribs on the outer ring and mounts the opposite way round; single-row NU1011 and N1011 have a fraction of the radial stiffness; a commercial-tolerance NN3011K holds a different accuracy class from an SP bearing.