SKF7208ACDP4ADGBSuper-Precision Angular Contact Ball Bearing 40x80x18 mm 25 Degree ABEC 7 Universal Matched Pair Moderate Preload

Product Description

What this part is

A super-precision angular contact ball bearing in the 7208 size, supplied as a factory-matched universal pair. Bore 40 mm, outside diameter 80 mm, width 18 mm per bearing.

Decoding the designation

7208 — ISO angular contact 72-series: 40 mm bore, 80 mm outside diameter, 18 mm width.
ACD — 25° contact angle in the SKF super-precision scheme. The A prefix is the 25° marker; a plain CD designation is 15°.
P4A — SKF super-precision class: ISO class 4 dimensional accuracy with class 2 running accuracy, the grade the trade calls ABEC 7.
DGB — matched set, universally ground, moderate preload. DGA is the light grade and DGC the heavy.

What these specs mean in practice

A 25° contact angle carries substantially more thrust and gives greater axial stiffness than the 15° CD design in the same envelope, in exchange for a lower speed limit and more heat generation. Moderate preload adds axial and radial stiffness over the light grade and holds running accuracy better under varying load, at the cost of higher friction and a higher steady-state temperature. Universal grinding means the pair develops its preload from the ground ring faces alone, with no shims or ground spacers.

Quantity and configuration

2 Pcs — one matched universal pair. The set can be arranged back-to-back, face-to-face or in tandem.

Fitting notes

The preload is ground into the ring faces and is realised only when both inner rings and both outer rings are clamped solidly against their seats. Alignment marks on the outer ring faces set the intended arrangement, and the two bearings stay together as a set.

Interchange guidance

Same-envelope 7208 bearings in the CD 15° design, or at the DGA and DGC preload grades, are related sizes rather than interchanges. The generic ISO shorthand for this size and angle is 7208 AC.