NSK7008ATYP4Super-Precision Angular Contact Ball Bearing – 40 mm ID, 68 mm OD, 15 mm Width, Open, 30° Contact Angle, P4

Product Description

What this part is

NSK 7008ATYP4 single-row super-precision angular contact ball bearing. Bore 40 mm, outside diameter 68 mm, width 15 mm. ISO 70 series, size 7008, straight bore, open both faces. Made in Japan.

Decoding the designation

Contact Angle: 30°, from the NSK A code. Cage Type: ball-guided, from TY. Arrangement: DB, back-to-back. Preload Class: C7. Precision Class: P4, ABEC 7. Series: ISO 70. Base Number: 7008.

Published ratings

Dynamic Load Rating Cr: 23.7 kN. Static Load Rating C0r: 14.6 kN. Limiting speed: 13,900 rpm on grease, 18,600 rpm on oil-air lubrication. Effective load centre a: 23.1 mm. Mass: 0.191 kg.

What these specs mean in practice

A 30° contact angle is the high-thrust end of the standard angular contact range, so this bearing carries more axial load and gives higher axial stiffness than a 15° or 25° bearing of the same envelope, at a lower speed ceiling. A ball-guided cage keeps cage mass low and suits the high speeds P4 grinding supports. P4 tolerances hold radial and axial runout tight, which shows up as lower running vibration and closer tool location on a spindle.

Quantity and configuration

One bearing. The DB code marks it as a back-to-back matched execution, ground to the C7 preload class, so preload is set by the ground faces rather than by a running clearance.

Fitting notes

Shaft abutment diameter da: 46 mm minimum. Housing abutment diameter Da: 62 mm maximum. Housing fillet radius ra: 1 mm maximum. Chamfer r: 1 mm minimum, r1: 0.6 mm minimum.

Interchange guidance

Fafnir 3MM9108WICRDU and FAG B7008E share the 40 x 68 x 15 mm envelope at a 25° contact angle, and SKF 7008 ACD/P4A does the same, so all three are related sizes rather than direct interchanges.