NHBBME-1104DLSuper-Precision Angular Contact Ball Bearing 20x42x12 mm 15° P4 Light Preload Duplex Pair

Product Description

What this part is

An NHBB ME-1104DL super-precision angular contact ball bearing set — two single-row bearings on the 7004 envelope, 20 mm bore by 42 mm outside diameter by 12 mm wide, ground and marked as a duplex pair at light preload. Open on both faces, no shields and no seals.

Decoding the designation

The designation is NHBB’s own super-precision scheme rather than an ISO code. ME is the metric super-precision angular contact family, 1104 is the size within it — the 7004 boundary dimensions — and DL is duplex construction at light preload. The listing’s cross to 7004-C-TPA-P4-DUL resolves the same part in ISO terms: C is a 15° contact angle, TPA a phenolic cage, P4 the ABEC 7 tolerance class, and DUL a duplex light-preload pair.

Published specifications

Bore: 20 mm (0.7874 in)
Outside diameter: 42 mm (1.6535 in)
Width per bearing: 12 mm (0.4724 in)
Total width of the pair: 24 mm (0.9449 in)
Contact angle: 15°
Precision class: P4, equivalent to ABEC 7
Preload: light (L)
Arrangement: duplex matched pair
Closure: open both faces
Cage: phenolic
Rows: 1 per bearing
Rolling elements: steel balls

What these specs mean in practice

A 15° contact angle sits at the high-speed, low-thrust end of the angular contact range: it takes less axial load than a 25° bearing of the same size but runs cooler and faster, which is why 15° dominates machine-tool spindle and high-speed instrument positions. Light preload holds the ball complement in defined contact for stiffness and runout control while adding the least heat of the three preload grades. P4 tolerances hold bore, outside diameter, and radial and axial runout to super-precision limits, and a duplex pair is ground so that the two rings clamp to the designed preload when the faces are drawn together.

Quantity and configuration

2 Pcs, supplied as one matched duplex pair at light preload.

Fitting notes

The pair mounts with the marked faces together, clamped through the ring faces so the ground offset sets the preload; shaft and housing seats are held to the fits appropriate to a P4 bearing.

Interchange guidance

7004-C-TPA-P4-DUL is the same specification under the ISO/Schaeffler-style code. A 7004 at 25° contact angle, or at a medium or heavy preload, or in a single universally ground execution, is a related size rather than an equivalent.