RHPBSB150DUHP4Ball Screw Support Bearing Matched Duplex Pair 1-1/2 in x 72 mm x 5/8 in 60 Degree Contact Angle Heavy Preload

Product Description

What this part is

A matched duplex pair of RHP BSB150 ball screw support bearings, 1-1/2 in bore, 72 mm outside diameter, 5/8 in wide each, ground to heavy preload. Ball screw support bearings are a distinct family built to take the axial thrust of a screw with very little radial duty.

Decoding the designation

In the RHP scheme BSB is the ball screw support series and 150 is the 1-1/2 in bore. DU marks the pieces as a ground duplex set, H is heavy preload and P4 is ABEC 7. The carton also carries the NSK number 38TAC72, and the NSK TAC family is 60°, which fixes the contact angle.

What these specs mean in practice

A 60° contact angle is far steeper than the 15° to 40° range of ordinary angular contact bearings. Nearly the whole load path runs along the shaft axis, giving very high axial stiffness and thrust capacity and very little radial capacity — the exact duty of a ball screw end support, where a separate journal takes radial load. Heavy preload raises axial stiffness further, which is what holds positioning accuracy on a feed axis under reversing load.

Quantity and configuration

2 Pcs, supplied as one matched duplex set. The rings are ground together so the pair reaches the specified heavy preload with the rings clamped solid. Each bearing is 5/8 in wide and the pair stacks to 1-1/4 in.

Thrust direction

Each bearing on its own takes thrust in one direction. Mounted back-to-back or face-to-face, the pair takes thrust in both directions, which is what a screw driven and braked in both directions needs; in tandem it takes a larger load in one direction only.

Interchange guidance

Bore is inch here: 1-1/2 in is 38.10 mm, while the NSK 38TAC72 on the same carton is a 38.00 mm metric bore, so that number is the family and angle reference rather than a drop-in swap. An ordinary 7000- or 7200-series angular contact bearing of similar section is not a substitute, because the shallower angle changes axial stiffness and thrust capacity. Light and medium preload versions of BSB150 are separate parts.