NDHUQ20213Super-Precision Angular Contact Ball Bearing 65 x 120 x 23 mm, 15 Degree Contact Angle, Universally Ground Single, Open, 1 Pc

Product Description

What this part is

A single New Departure Hyatt super-precision angular contact ball bearing in the 7213 envelope — 65 mm bore, 120 mm outside diameter, 23 mm width. Open, 15° contact angle, universally ground. New old stock American spindle-grade product, for machine-tool spindles, grinding heads, precision rotary tables and high-speed shafts carrying combined radial and one-direction thrust load.

Decoding the designation

20213 — NDH’s number for the ISO 7213 size, 65 x 120 x 23 mm. In the NDH scheme the 20-series prefix is the 15° angular contact family; the 30-series is the steeper 40° build.
UQ — universally ground super-precision, so two bearings of the same code mate in any orientation to form a preloaded set.
No DT or DU suffix follows, so this is supplied as a single bearing rather than as a tandem or duplex set.

What these specs mean in practice

A 15° contact angle is the high-speed end of the angular contact range. The shallow angle keeps the ball load closer to radial, which cuts centrifugal ball loading and the heat it generates, so the bearing turns faster and cooler than a 40° build of the same size — and carries appreciably less thrust while offering less axial stiffness. On a 65 mm bore that is a meaningful choice: this is a spindle bearing, sized for accuracy and speed rather than for heavy axial thrust. Universal grinding is what makes it easy to build with. The ring faces are ground to a calculated stand-off, so clamping two together sets a defined preload with nothing to shim and no risk of crushing the set. Super-precision running accuracy only reaches the shaft if the mating hardware earns it — ground, clean, burr-free seats, checked for roundness. A worn housing bore will erase the whole benefit.

Quantity and configuration

1 Pc — one bearing. Universally ground, so if the spindle needs a preloaded set, two bearings of this same code clamped together will give one.

Fitting notes

Angular contact bearings take thrust in one direction only, so the assembly must oppose it — a second bearing, a spring pack or a shoulder. Orientation matters: the wide land of the outer ring faces the thrust load. Interference fit adds preload on top of anything ground in, so check shaft and housing sizes against the spindle drawing before pressing. Never press through the ball complement, and induction-heat rather than hammer a 65 mm bore onto a tight shaft. Lubricate sparingly with a spindle grease or run oil-air; over-greasing a 15° bearing at speed is a reliable way to cook it.

Interchange guidance

New Departure Hyatt was General Motors’ bearing division and the brand is long out of production, so buyers cross-referencing to a current maker want the ISO number: 7213 at 15°. Genuine same-angle cross-references in this envelope include SKF 7213 CD/P4A, FAG B7213-C-T-P4S, NSK 7213C and Fafnir/Timken 2MM9113WI. Related sizes fill the identical 65 x 120 x 23 mm envelope at other contact angles — 7213AC and 7213 ACD are 25°, 7213B is 40°, and NDH’s own 30213 is the 40° version of this number. Those are different parts with different thrust capacity and speed ratings, not substitutes, but worth knowing if your spindle drawing calls for a steeper angle.