SNR7008HG1DUJ84Super Precision Angular Contact Bearing Pair 40x68x15 mm 25° Duplex Universally Ground

Product Description

What this part is

An SNR 7008HG1DUJ84 matched duplex pair of super-precision angular contact ball bearings. Each bearing has a 40 mm bore, a 68 mm outside diameter and a 15 mm width, giving a 30 mm stack height for the pair.

Decoding the designation

7008 — 70 angular contact series, 40 mm bore, 68 mm OD, 15 mm widthH — 25° contact angle in the SNR super-precision schemeG1 — super-precision ground executionDU — duplex universally ground, so any two bearings of this designation mount together as a matched setJ84 — SNR factory matching and preload code, retained as a search term

What these specs mean in practice

A 25° contact angle gives high axial rigidity and thrust capacity for a given envelope, which is what a boring or milling spindle needs when the cut pushes along the axis. The 15° version of the same size spins faster and deflects more axially. Universal grinding lets any two bearings of this designation be paired back-to-back, face-to-face or in tandem, with the preload set by clamping the rings flush rather than by shimming.

Published specifications

Bore: 40 mm (1.5748 in)Outside diameter: 68 mm (2.6772 in)Width per bearing: 15 mm (0.5906 in)Contact angle: 25°Number of rows: 1 per bearingRolling elements: steel ballsClosure: openArrangement: duplex universally ground pair

Quantity and configuration

Supplied as 2 Pcs, a matched duplex pair.

Fitting notes

Duplex pairs mount with the ground faces butted and the rings clamped so the built-in offset develops the preload. Orientation determines whether the mount takes thrust in both directions (back-to-back or face-to-face) or in one direction at doubled capacity (tandem).

Interchange guidance

Genuine equivalents are 25° super-precision universally ground bearings in the same 40x68x15 mm envelope: FAG 7008-E-T-P4-DUM, NSK 7008A5, SKF 7008 ACD/P4A and Fafnir 3MM9108WI-DUM. The 15° build of this size is a related size rather than an interchange, because it changes axial rigidity and preload behaviour.