SNFASEB17-7CE1DUHSuper-Precision Angular Contact Ball Bearing Matched Pair – Straight Bore, 17 mm ID, 30 mm OD, 7 mm Width, Open, 15° Contact Angle, Heavy Preload, Phenolic Cage, ABEC 7

Product Description

What this part is

SNFA SEB17-7CE1DUH is a duplex matched pair of super-precision angular contact ball bearings, 17 mm bore by 30 mm outside diameter by 7 mm width per bearing, 14 mm across the mounted pair. The ISO equivalent designation is 71903, the thin 719 dimension series. Both bearings are open, with a phenolic resin cage and a straight bore. SNFA is a French super-precision manufacturer, now part of the SKF group.

Decoding the designation

The carton carries the SNFA number with its ISO and Fafnir equivalents, and all three agree. In SEB17-7CE1DUH, SEB is the SNFA series that maps to the ISO 719 family, 17 is the bore in millimetres, the 7 is the ABEC class, CE1 gives a 15° contact angle and DUH is a duplex universal set at heavy preload. The 7903-C-T-P4-DUH reading gives C for 15°, T for a phenolic cage and P4 for ABEC 7. The Fafnir 2MM9303WI-CR-DUH reading gives 2MM for 15°, the 9300 prefix that maps to ISO 719, and CR for a phenolic outer-land-riding cage.

What these specs mean in practice

A 15° contact angle favours speed and radial stiffness over thrust capacity. Heavy preload is the stiffest rung of the preload ladder: it gives the highest axial and radial rigidity and the tightest running accuracy under load, at the cost of more friction, more heat and a lower permissible speed than a light or medium set. The phenolic cage suits high shaft speeds and sets the practical temperature ceiling at 120°C.

Quantity and configuration

Two pieces, supplied as one matched pair. The rings are universally ground, so the pair mounts back-to-back, face-to-face or in tandem and develops the specified heavy preload in any of those arrangements. The set is preloaded rather than clearance-set, so no internal clearance class applies.

Fitting notes

The bore is straight and both bearings are supplied without a snap ring, so axial location comes from the housing shoulder and the clamping arrangement. A heavy-preload set generates more heat than a lighter one, so oil lubrication and attention to housing fit suit it better than grease at the top of its speed range.

Interchange guidance

SKF 71903 CD/P4ADGC is the direct equivalent, matching on envelope, 15° angle, ABEC 7 class and heavy preload. Fafnir 2MM9303WI-CR-DUH is the same set in Timken numbering, and NSK 7903CTRDUHP4 is the NSK equivalent with the same phenolic cage. A DUL or DUM suffix on any of these numbers denotes light or medium preload, which is a different rigidity and a related item rather than a substitution, and a 71903 ACD or 3MM9303WI is a 25° bearing on this envelope.