URBNN3014MNASP51W33Double Row Cylindrical Roller Bearing 70x110x30 mm, Cylindrical Bore, Brass Cage, P5 / C1, W33 Lube Groove

Product Description

What this part is

A URB NN3014 double-row cylindrical roller bearing, 70 mm bore x 110 mm outside diameter x 30 mm wide, with a straight cylindrical bore, a machined brass cage and a W33 lubrication groove in the outer ring. Two rows of rollers in a low cross-section give it very high radial capacity and very high radial stiffness for its envelope, which is why the NN30 series is the standard choice for machine-tool spindles, gearbox output shafts and rolling-mill roll necks.

Decoding the designation

NN — double row, ribs on the inner ring, outer ring without ribs. The outer ring lifts straight off the roller set.
30 — ISO dimension series 30 (medium section).
14 — 70 mm bore.
M — machined brass cage, roller-guided.
NA — non-interchangeable radial internal clearance. The inner and outer ring are ground as a matched pair.
S / W33 — annular lubrication groove and three radial holes in the outer ring.
P51 — P5 tolerance class with C1 (reduced) radial internal clearance.
No K — straight cylindrical bore, not the 1:12 taper.

What these specs mean in practice

Because the outer ring has no ribs, this bearing is non-locating. It takes radial load only and allows the shaft to expand and contract axially inside the outer ring. It must be paired with a separate locating bearing at the other end of the shaft — on its own it will not hold a shaft in position. That is the design intent, not a limitation: it is what lets a spindle grow thermally without preloading itself to death.

The straight bore means clearance is set by the interference fit you press on, not by drawing the inner ring up a taper. If you need to dial in clearance or preload at assembly, that is the tapered-bore NN3014K, which is a different part. P5 tolerance with C1 clearance is a precision, tight-running combination — use recommended spindle fits, not general-industry fits, or the C1 clearance will disappear.

The machined brass cage tolerates higher temperature and shock loading than a polyamide cage and is the usual choice where the lubricant is oil or oil-air.

Published mounting data

Bore d: 70 mm
Outside diameter D: 110 mm
Width B: 30 mm
Outer-ring raceway diameter E: 100 mm
Chamfer r min: 1.1 mm
Shaft abutment diameter da: 76.5 mm
Housing abutment diameter Da: 103.5 mm
Approximate mass: 1.04 kg
Rows: 2 — Cage: machined brass, roller-guided — Closure: open

Quantity and configuration

Sold as 1 Pc — one complete bearing: outer ring, plus inner ring with both roller rows and cages. Because the clearance is non-interchangeable, keep this outer ring with this inner ring; do not mix rings between bearings.

Fitting notes

Separable design: the outer ring can be fitted to the housing and the inner ring and roller assembly to the shaft independently, which is the reason this type is chosen where both rings need an interference fit. Line up the W33 holes in the outer ring with the housing lubrication feed. Never drive the roller set in through the outer ring at an angle — cocking it brinells the raceway before the spindle ever turns.

Interchange guidance

Dimensionally interchangeable with NN3014 double-row cylindrical roller bearings from other makers — SKF NN 3014, FAG NN3014-AS-M-SP, NSK NN3014, NTN NN3014, Nachi NN3014, Koyo NN3014 — provided you match the bore type, tolerance class and clearance. Related sizes are not substitutes: NN3014K is the 1:12 tapered-bore version and will not fit a straight shaft seat; NNU4914 shares nothing but a rough size class and puts the ribs on the outer ring; and a single-row NU214 or N214 in a similar envelope has roughly half the radial capacity and different stiffness. Check the tolerance class as well — a P0 commercial NN3014 is not a drop-in for this P5/C1 unit in a precision spindle.