NTN7007CGD2GNP4Super Precision Angular Contact Ball Bearing Matched Duplex Pair, 35 x 62 x 14 mm, 15 Degree Contact Angle, ABEC 7, Phenolic Cage, Universally Ground

Product Description

What this part is

A factory-matched duplex pair of super precision angular contact ball bearings in the 7007 envelope — 35 mm bore, 62 mm outside diameter, 14 mm width per bearing, single row each. This is a machine-tool spindle bearing, not a general-purpose bearing: the rings are ground to ABEC 7 geometry and matched to each other so the pair develops a defined preload when clamped up.

Decoding the designation

7007 – ISO angular contact ball bearing, 35 mm bore, 10 series envelope.
C – 15° nominal contact angle.
GD2 – duplex universal grind: ring faces relieved so two bearings mount together in any of the three arrangements with the intended preload. NTN’s GD2 with a trailing preload letter reads as GD2GL for light preload, GD2GM for medium.
GN – NTN cage and lubrication/greasing code.
P4 – ABEC 7 precision class. The carton uses NTN’s older B7 notation for the same class.
1E – a trailing factory pairing or lot code on the carton. NTN does not publish a decode for it and none is invented here.

Reading the carton, not the catalogue

The carton in the photographs is printed 7007CGD2/GNB7/1E, with the box numbers 431-17 B and No. J 1477 A, and a date code of 82-05. A green band across the lid reads USED IN PAIR FOR PRECISION. The catalogue-style designation carried in the listing title, 7007-C-GD2-GN-P4, is the same bearing written in NTN’s modern suffix order. Both forms are given so either search finds it. Note that the preload class letter (L, M or H) does not appear anywhere on this carton, so the exact preload grade of this set is not documented — the pairing is factory-matched but its grade is unstated.

What these specs mean in practice

The 15° contact angle is the high-speed configuration. A shallower angle keeps more of the load path radial, which reduces the centrifugal and gyroscopic loading on the ball set and lets the bearing turn faster and cooler than a 25° bearing of the same size. What you give up is axial stiffness under heavy thrust; a 25° bearing holds the spindle nose in position better when a cut is pushing hard along the axis.

The cage in this pair is visibly a brown machined phenolic laminate, riding on a ring land. Phenolic is the classic spindle-bearing cage material because it is light, self-lubricating and quiet at speed, and because it flexes rather than fretting the balls. Its limit is temperature and chemistry: phenolic will soften and delaminate above roughly 120 °C and dislikes some synthetic oils, so it belongs in an oil-mist, oil-air or grease-for-life spindle, not a hot high-load application.

Universally ground rings mean the fitter chooses the arrangement rather than the part number. Back-to-back gives the widest effective load-line spread and the greatest moment stiffness, which is what a spindle nose wants. Face-to-face tolerates a little shaft-to-housing misalignment. Tandem doubles axial capacity in one direction only.

Published ratings and mounting data

NTN does not publish dynamic load rating, static load rating or limiting speed for the legacy 7007CGD2/GNB7 designation in any current or reachable source; figures for this line survive only in out-of-print paper catalogues. Nothing is estimated or borrowed here from a sibling part or another manufacturer, because cage material and preload grade both move limiting speed by a wide margin. Boundary dimensions are ISO-standardised and are stated above.

Quantity and configuration

One lot equals one matched pair equals two physical bearings. The stock quantity of 1 is one saleable pair, and that is correct rather than a data error. The photographs confirm it: the wrapped assembly is two bearings stacked, with two outer rings and two offset inner rings visible in the unwrapped view. Keep the pair together — a matched set split between two machines loses the matching it was ground for.

Fitting notes

The condition note records dried grease, which is normal for a 1982-dated new old stock spindle bearing. Wash the pair in clean solvent and relubricate to your spindle’s specification before fitting; do not run it on the original grease. Clamp against square shoulders and a square nut or spacer face — the preload lives in the ground ring faces and a cocked clamp destroys it. Keep the bearings wrapped until the moment of assembly and handle them by the outer ring.

Interchange guidance

Equivalent designation forms include 7007CGD2GNP4, 7007 C GD2 GN P4, 7007CGD2/GNB7, 7007CGD2GLP4 and 7007CDU. The historical cross into the Timken/Fafnir super precision line is 2MM9107WI CR DU, an inch-series-marked but metric-envelope 35 x 62 x 14 bearing with a phenolic outer-land-riding cage. Same-envelope equivalents exist as NSK 7007CTYDULP4, FAG B7007-C-T-P4S and SKF 7007 CD/P4A, but preload grade and cage material differ between brands, so match the full suffix rather than the base number alone. NTN and SNR now trade jointly as NTN-SNR.