SNR7204HG1DUJ84Super Precision Angular Contact Bearing Pair 20x47x14 mm 25° Duplex Universally Ground

Product Description

What this part is

An SNR 7204HG1DUJ84 matched duplex pair of super-precision angular contact ball bearings. Each bearing has a 20 mm bore, a 47 mm outside diameter and a 14 mm width, giving a 28 mm stack height for the pair.

Decoding the designation

7204 — 72 angular contact series, 20 mm bore, 47 mm OD, 14 mm widthH — 25° contact angle in the SNR super-precision schemeG1 — super-precision ground executionDU — duplex universally ground, so any two bearings from 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 sits at the stiff end of the spindle range. It carries more thrust and gives higher axial rigidity than a 15° bearing of the same envelope, at the cost of a lower speed ceiling. Universal grinding means the faces are ground so the pair can be set back-to-back, face-to-face or in tandem without shims, and the preload comes up correctly when the rings are clamped flush.

Published specifications

Bore: 20 mm (0.7874 in)Outside diameter: 47 mm (1.8504 in)Width per bearing: 14 mm (0.5512 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 are installed with the ground faces butted and the inner rings clamped together so the built-in offset generates the preload. Orientation of the two bearings sets whether the mount takes thrust in both directions (back-to-back or face-to-face) or in one direction with doubled capacity (tandem).

Interchange guidance

Genuine equivalents are 25° super-precision universally ground bearings in the same 20x47x14 mm envelope: FAG 7204-E-T-P4-DUM, NSK 7204A5, SKF 7204 ACD/P4A and Fafnir 3MM204WI-DUM. The 15° version of this size, coded C in the SNR and NSK schemes, is a related size rather than an interchange: it changes axial rigidity and preload behaviour.