NSK7034A5TRSULP4Super-Precision Angular Contact Ball Bearing – 170 mm ID, 260 mm OD, 42 mm Width, Open, 25° Contact Angle, Phenolic Cage, P4

Product Description

What this part is

NSK 7034A5TRSULP4 single-row super-precision angular contact ball bearing. Bore 170 mm, outside diameter 260 mm, width 42 mm. ISO 70 series, size 7034, straight bore, open both faces. Made in Japan.

Decoding the designation

Contact Angle: 25°, from the NSK A5 code. Cage Type: machined, outer-ring guided. Cage Material: fabric-base laminate phenolic, from TR, rated to 120 °C. Grouping: SUL, single universally ground to light preload. Precision Class: P4, ABEC 7. Series: ISO 70. Base Number: 7034.

Published ratings

Dynamic Load Rating Cr: 244 kN. Static Load Rating C0r: 223 kN. Limiting speed: 4,200 rpm on grease, 6,600 rpm on oil-air lubrication. Effective load centre a: 71.1 mm. Permissible axial load Pa: 168 kN. Mass: 7.83 kg.

What these specs mean in practice

A 25° contact angle carries substantially more thrust and gives more axial stiffness than a 15° bearing of the same envelope, at a lower speed ceiling. An outer-ring guided phenolic cage runs light and self-lubricating, which is what lets a 170 mm bore turn at 6,600 rpm under oil-air, and it holds up to 120 °C. Light preload removes play while keeping heat generation low. P4 tolerances hold radial and axial runout tight, giving lower running vibration and closer tool location.

Quantity and configuration

One bearing, universally ground to light preload. Universal grinding lets it pair with any other bearing of the same designation back-to-back, face-to-face or in tandem, arriving at the ground preload with no spacer grinding.

Fitting notes

Shaft abutment diameter da: 182 mm minimum. Housing abutment diameter Da: 248 mm maximum. Housing fillet radius ra: 2 mm maximum. Chamfer r: 2.1 mm minimum, r1: 1.1 mm minimum. Grease charge: 40 g per bearing.

Interchange guidance

SKF 7034 ACDGA/P4A is the same size at the same 25° contact angle and light preload class. Fafnir 3MM9134WI-SUL is the Timken cross for this envelope and grouping. GMN S6034CTA and FAG B7034-E-P4-UL cover the same size at 25°.