SKF7209-ACD/P4A-DGCSuper-Precision Angular Contact Ball Bearing Matched Set – 45 mm ID, 85 mm OD, 19 mm Width, Open, 25°, P4A, Heavy Preload

Product Description

What this part is

SKF 7209 ACD/P4ADGC is a matched set of two super-precision single-row angular contact ball bearings, 45 mm bore, 85 mm outside diameter, 19 mm width per bearing. Open on both faces, with 14 balls of 12.7 mm diameter per bearing and an outer-ring-riding machined phenolic cage.

Decoding the designation

7209 is the ISO 72 series in the 09 bore code, giving a 45 mm bore. AC denotes a 25° contact angle and D the outer-ring-riding cage design. P4A is the SKF super-precision tolerance class. DGC denotes a universally matchable set of high-precision angular contact ball bearings ground for heavy preload; the SKF preload ladder runs DGA light, DGB medium, DGC heavy, and for the 7209 size the class C preload value is 1040 N.

What these specs mean in practice

A 25° contact angle carries more thrust and less speed than a 15° bearing of the same envelope, and less thrust with more speed than a 40°. Heavy preload gives the highest axial and radial stiffness of the three SKF preload classes, holding shaft position under cutting or reversing loads, and in exchange raises running friction and heat generation. The phenolic cage is light and outer-ring guided, which suits high speed and lubricant carrying. Basic dynamic load rating C is 41 kN and basic static load rating C0 is 30 kN per bearing, with a fatigue load limit of 1.2 kN.

Quantity and configuration

Two bearings, sold as one matched set, 38 mm total width when mounted adjacent. Universal matchability means the set mounts back-to-back, face-to-face or in tandem, with the heavy preload established by clamping the ground ring faces together. Because the set is preloaded, no radial internal clearance class applies.

Fitting notes

Preload arises directly from the ground ring faces, so shims and spacers are not used. Limiting speed is 15 000 r/min on grease and 24 000 r/min on oil for a single bearing; a heavy-preload pair runs below those figures. Mass is 0.41 kg per bearing.

Interchange guidance

FAG B7209-E-T-P4S-DUH is a direct interchange: 25°, phenolic cage, P4S, universally matchable heavy preload. Timken 3MM209WI CR DUH and NSK 7209A5TRDUHP4 are the same specification in their own schemes. 7209 ACD/P4ADGA and 7209 ACD/P4ADGB are related sizes at light and medium preload respectively. 7209 CD/P4ADGC is a related size at a 15° contact angle.