SKF71913-ACDGB/P4ASuper-Precision Angular Contact Ball Bearing Matched Pair 65 x 90 x 13 mm, 25° Contact Angle, Medium Preload, ABEC 7, Back-to-Back, 26 mm Total Width

Product Description

What this part is

A matched pair of single-row super-precision angular contact ball bearings in the 719-series, 65 mm bore, 90 mm outside diameter, 13 mm width per bearing. The 719 series is the extra-thin-section angular contact family, and the rings are ground as a set for back-to-back mounting at a defined medium preload.

Decoding the designation

71913 — single-row angular contact ball bearing, 65 mm bore, 719 extra-light dimension series
AC — 25° contact angle in the SKF scheme
CD — super-precision execution
DGB — matched pair, back-to-back, medium preload
P4A — ABEC 7 precision class, SKF super-precision tolerance

What these specs mean in practice

The 719 cross-section is thin for its bore, which keeps the bearing set compact axially and lets a large shaft run inside a small housing bore — the reason it appears in tool spindles, rotary tables and direct-drive heads where space around the shaft is short. A 25° contact angle carries more thrust and gives higher axial stiffness than a 15° execution of the same 65 x 90 x 13 mm envelope, at a lower speed ceiling. Medium preload sits between the light setting chosen for maximum speed and the heavy setting chosen for maximum rigidity. Back-to-back mounting places the load lines diverging outward, which resists moment loads and holds the shaft square.

Quantity and configuration

2 Pcs, one matched pair. Total mounted width of the pair is 26 mm.

Fitting notes

The pair mounts in its ground orientation with the etched face markings aligned so the two outer rings meet at their narrow faces. Both rings are clamped fully home so the preload comes off the ground faces rather than off clamp force, and the thin cross-section makes a square, well-supported shoulder and a round housing bore important to the running accuracy.

Interchange guidance

Same-spec equivalents are 25° ABEC 7 medium-preload back-to-back 71913-size pairs under other schemes, such as an NSK 7913A5TRDUM or an FAG B71913-E-T-P4S-DUM. SKF 71913 CDGB/P4A at 15°, 71913 ACDGA/P4A at light preload, and hybrid HCP4A executions are related sizes rather than interchanges.