NSKSuper Precision Angular Contact Ball Bearing 25x52x15 mm, 25 Degree Contact Angle, Duplex Universally Ground Medium Preload

Product Description

What this part is

NSK 7205A5TYDUMPA7, a super-precision angular contact ball bearing in the 72-dimension series, 25 mm bore by 52 mm outside diameter by 15 mm width, with a 25° contact angle, universally ground as a duplex set at medium preload. Brand: NSK. Bearing Type: Super-precision angular contact ball bearing. Bore: 25 mm. Outside Diameter: 52 mm. Overall Width: 15 mm per bearing. Contact Angle: 25°. Preload: Medium. Arrangement: DUM, duplex universally ground, mountable back-to-back, face-to-face or tandem. Number Of Rows: Single row per bearing. Rolling Elements: Steel balls. Bearing Material: High carbon chrome steel. Closure Type: Open. Series: 72, ISO 02 dimension series. Base Number: 7205A5. Design Units: Metric. Harmonization Code: 8482.10.50. A machine tool spindle bearing.

Published ratings

Dynamic Load Rating: 15.7 kN. Static Load Rating: 9.65 kN. Limiting Speed: 25,800 rpm on grease, 38,500 rpm on oil. Operating Temperature Range: -30 °C to 120 °C. These figures are for the single 7205A5 bearing; a preloaded duplex set runs a lower practical speed than a single free bearing.

Decoding the designation

7205: 72-dimension series angular contact ball bearing, 25 x 52 x 15 mm. A5: Contact Angle 25° in NSK’s scheme, where C is 15°, A5 is 25°, A is 30° and B is 40°. DUM: duplex universally ground, medium preload, with the faces ground so the set produces its specified preload when clamped together in whichever arrangement is chosen. Searchable variants: 7205A5TYDUMPA7, 7205-A5-TY-DUM-PA7, 7205 A5 TY DUM PA7, 7205A5TYNDUMPA7, 7205A5DUM, 7205A5.

What 25° and medium preload buy

25° is the middle spindle angle. It carries substantially more thrust and gives more axial stiffness than a 15° bearing, without the speed and heat penalty of a 30° or 40° bearing. It is the usual choice for milling and machining centre spindles that carry real cutting thrust and still need to turn quickly. Medium preload gives greater stiffness and positional accuracy than a light-preload set, at the cost of more heat and slightly less speed headroom. Preload is ground into the faces, so the class is fixed at purchase.

Contact angles match across a spindle stack. A 25° bearing paired with a 15° bearing absorbs most of the thrust while the shallower one runs underloaded and skids.

Quantity and configuration

DUM designates bearings ground as a matched set. Bearings ground as a common set produce the specified preload when clamped together.

Interchange guidance

Designations at 25° in this envelope: 7205AC in SKF format, where AC denotes 25°; B7205-E in Schaeffler format, where E denotes 25°; the 3MM205WI family in Fafnir and Timken format, where the 3MM prefix denotes 25°. 7205C is 15° and 7205A is 30°; both share this envelope and carry different thrust capacity and speed.