FAGNN3016KMSP5Precision Double-Row Cylindrical Roller Bearing, 80x125x34 mm, Tapered 1:12 Bore, Machined Brass Cage, SP Precision Class

Product Description

What this part is

A double-row cylindrical roller bearing in the NN30 precision series, 80 mm bore by 125 mm outside diameter by 34 mm wide, with a tapered bore and a machined brass cage. This is the classic front bearing of a precision machine-tool spindle: two rows of closely spaced rollers give very high radial load capacity and radial stiffness in a short axial length.

Decoding the designation

NN — double-row cylindrical roller bearing
30 — dimension series
16 — bore code, 80 mm
K — tapered bore, taper 1:12
M — solid machined brass cage
SP — precision class: broadly P5 dimensional tolerance with P4-level running accuracy, the standard spindle grade for this series
W33 (on the alternate number) — lubrication groove and three feed holes in the outer ring
P51 and NA (on the alternate number) — supplier-scheme suffixes with no published decode; carried as search terms only

Correcting the source data

Two things were cleaned up. The brand fields disagreed with each other — the title read “Cons” (Consolidated) while the brand field and body copy said FAG. That conflict has been flagged internally and the brand left as found rather than guessed at; if the exact make matters to your application, ask us to read the ring etching before you order. Separately, the previous copy quoted a 129 kN dynamic and 183 kN static rating and a −40 to 150 °C range with no traceable source. Those figures have been removed rather than repeated, because a rating attached to the wrong maker’s variant of an NN3016 is worse than no rating at all.

What these specs mean in practice

The point of a double-row cylindrical roller bearing is radial rigidity per millimetre of spindle length — nothing beats it for holding a boring or grinding spindle steady under cutting load. The trade-off is absolute: it carries no axial load and provides no axial location. It always works in combination with something that does, typically an angular contact set or a double-direction thrust bearing at the rear. A spindle built on NN bearings alone will float axially.

Fitting notes

The tapered bore is not an inconvenience, it is the adjustment mechanism. Radial internal clearance in this bearing is set by how far the inner ring is driven up the 1:12 taper of the spindle nose, measured as bore expansion or as residual clearance, not by feel. Get it wrong tight and the spindle overheats and seizes; wrong loose and you lose the rigidity you paid for. Use the manufacturer’s drive-up figures and measure. Because the bore is tapered, the bearing will not fit a plain cylindrical shaft without an adapter sleeve.

Published ratings and mounting data

Boundary dimensions 80 x 125 x 34 mm and the 1:12 taper are confirmed as the ISO NN30-series values. Basic dynamic rating, basic static rating and limiting speed are deliberately left blank: they differ between makers’ NN3016K variants, and no manufacturer-published figure could be verified for the specific bearing in hand.

Interchange guidance

Same-envelope precision equivalents include NSK NN3016TBKRCC0P4, NTN NN3016KC1NAP4, SKF NN 3016 KTN9/SP and FAG NN3016-AS-K-M-SP. Straight-bore siblings drop the K and are not interchangeable with a tapered spindle seat. Where the alternate number includes W33, confirm your housing actually feeds oil to the outer-ring groove — a W33 bearing in a dry housing simply runs as an ordinary one.