NSK7213ASingle-Row Angular Contact Ball Bearing 65 x 120 x 23 mm, 30 Degree Contact Angle, Open, Duplex-Capable

Product Description

What this part is

A single-row angular contact ball bearing in the 7200 (ISO dimension series 02) envelope: 65 mm bore, 120 mm outside diameter, 23 mm width. Open on both sides, so it is lubricated by the housing and relies on the mounting arrangement for axial location.

Decoding the designation

72 – single-row angular contact ball bearing, dimension series 02.13 – bore code; 13 x 5 = 65 mm bore.A – 30° nominal contact angle in NSK’s scheme. This matters: in the same 65x120x23 envelope NSK also builds 7213C at 15° and 7213B at 40°. The rings are not interchangeable in behaviour even though they drop into the same bore and housing.DB (as in the carton designation 7213AWDBCP10) – back-to-back duplex arrangement. Two bearings mounted outer-ring-face to outer-ring-face, which spreads the load lines apart and gives the stiffest resistance to overturning moments of the three duplex options.W and CP10 – further NSK supplementary designations carried on the carton for this lot. They are retained here as searchable cross-references; we do not publish a value for them because NSK’s own definition for these particular codes is not available to us, and guessing at a preload figure on a preload-sensitive product would be worse than saying nothing.

What a 30 degree contact angle buys and costs

Contact angle is the single biggest decision on an angular contact bearing. At 30° the load line through the balls is steeper than the 15° variant, so the bearing takes substantially more axial thrust in its designed direction and resists axial deflection better. The trade is speed and radial capacity: a steeper angle raises ball spin and cage loading, which is why the 30° grease-lubricated limiting speed here is 6,000 rpm rather than the higher figures quoted for the 15° C-suffix version. If the application is a high-speed grinding or milling spindle, 15° is usually the right answer. If it is a worm drive, a vertical pump shaft, a screw-jack or a gearbox output taking real thrust, 30° is.

Published ratings and mounting data

Basic dynamic radial load rating Cr: 70,500 N (7,150 kgf), per ISO 281 at one million revolutions.Basic static radial load rating C0r: 58,000 N (5,900 kgf).Limiting speed: 6,000 rpm grease, 8,500 rpm oil — single bearing values. De-rate for duplex sets and for preloaded mountings.Effective load centre a: 38.2 mm from the ring face. This is the number you need to calculate the true span between bearing load lines, not the physical bearing spacing.Shaft abutment (backing shoulder) diameter da: 74.0 mm. Housing abutment diameter Da: 111.0 mm. Maximum shaft/housing fillet radius ra: 1.5 mm.Ring chamfers: r min 1.5 mm (inner), r1 min 1.00 mm (outer).Mass: approximately 1.03 kg (2.27 lb) per bearing.

Quantity and configuration — read this before ordering:
Each unit is one single bearing. The carton designation for this lot includes a DB duplex reference because the original packaging described a back-to-back matched pair, but these are held and sold as loose singles out of a larger quantity. They are not supplied as a factory-matched, ground-to-preload set unless specifically confirmed. If your spindle needs a matched pair with a controlled preload offset, ask us to verify the carton markings on the specific pieces before you buy — two unmatched singles bolted back-to-back will not produce a predictable preload.

Fitting notes

An angular contact bearing carries thrust in one direction only, so a single bearing must be axially opposed by something — a second angular contact bearing, a deep groove bearing, or a shoulder and locknut. Observe the abutment diameters above: clamping over too large a shoulder on the outer ring will pinch the raceway and destroy the internal geometry. Do not interchange the inner and outer rings between bearings; the balls and rings are matched at assembly.

Interchange guidance

The 65x120x23 mm angular contact envelope is built by every major maker, but the contact angle usually differs. Same boundary dimensions: NSK 7213A (30°), NSK 7213C (15°), NSK 7213B (40°), FAG/Schaeffler 7213-B-XL-TVP / -MP / -JP (40°), SKF 7213 BECBM (40°), NTN 7213, Koyo 7213, NACHI 7213. Match the contact angle, not just the dimensions. Dropping a 40° B-suffix bearing into a position designed around a 30° A-suffix bearing changes the load line, the stiffness and the calculated life. Note also that some suppliers list this size under the 7213E designation; treat that as a dimensional cross-reference and confirm the angle.