NSK7213CTRDUHP4YSuper-Precision Angular Contact Ball Bearing – Straight Bore, 65 mm ID, 120 mm OD, 23 mm Width, Open, 15° Contact Angle, Heavy Preload, Universally Ground, P4Y

Product Description

What this part is

NSK 7213CTRSUHP4Y super-precision angular contact ball bearing. Bore 65 mm, outside diameter 120 mm, width 23 mm. Straight bore, open on both faces, single row of balls, machined phenolic cage riding on the outer ring land.

Decoding the designation

72 is the ISO medium angular contact dimension series and 13 is the bore code, giving a 65 mm bore. C denotes a 15° contact angle in the NSK scheme. TR is an outer-ring-guided phenolic cage. U marks universal grinding and H sets heavy preload. P4Y is an NSK special accuracy class held tighter than P4, which the carton also states as ABEC7.

What these specs mean in practice

A 15° contact angle favours speed and radial stiffness over thrust capacity, which is the usual choice for a high-rpm grinding or milling spindle. Heavy preload takes stiffness and running accuracy to their maximum for that angle, holding shaft position under interrupted cut, and pays for it in heat generation and a lower speed ceiling. Guiding the phenolic cage on the outer ring land keeps it stable at the top of the speed range, and the P4Y class holds ring runout inside the ordinary P4 limits.

Quantity and configuration

One piece. Universal grinding means any two units of this designation stack directly as a back-to-back, face-to-face or tandem set, with the heavy preload built into the ground ring faces. A single-row angular contact bearing takes thrust in one direction, so a second bearing opposes it.

Fitting notes

Ring faces are ground flat and square for direct abutment, so preload develops when the shaft nut and housing cap are drawn fully home. Phenolic cages suit oil mist and circulating oil lubrication.

Interchange guidance

Same 15° heavy-preload equivalents are the SKF 7213 CDGC/P4A and the FAG B7213-C-T-P4S-UH. The Fafnir 2MM213WI-SUH is the same specification under the WI numbering scheme. Those numbers are ordinary P4 class, so they run a looser accuracy than this P4Y bearing.