NDHQ30211DTL7AAngular Contact Ball Bearing Triplex Matched Set 55x100x21 mm ABEC-7 Light Preload Phenolic Separator

Product Description

What this part is

New Departure Hyatt Q30211DTL7A single-row angular contact ball bearings, 55 mm bore, 100 mm outside diameter, 21 mm width each. Open on both faces, phenolic ball separator, all faces flush ground as one universally mountable matched set.

Decoding the designation

Q – nonmetallic (phenolic) ball separator
30211 – New Departure 30200 angular contact series; 55 x 100 x 21 mm envelope, matching ISO 7211
DT – matched set with all bearing faces flush ground to preload requirement, for universal mounting in tandem, back-to-back or face-to-face
L – light preload
7 – ABEC-7 tolerance class
A – rust-preventive slush

What these specs mean in practice

A universally ground set can be stacked in any of three arrangements from the same parts: tandem for one-direction thrust shared across rows, back-to-back for a wide effective load span and high moment stiffness, face-to-face for a narrow span that tolerates more shaft misalignment. Light preload is the lowest of the three NDH classes — L light, X medium, T heavy — and trades stiffness for lower running torque, less heat and higher usable speed. ABEC-7 is the precision grade used for machine tool spindle positions.

Published specifications

Bore: 55 mm (2.1654 in)
Outside diameter: 100 mm (3.9370 in)
Width, each bearing: 21 mm (0.8268 in)
Rows: 1 per bearing
Rolling element: ball
Closure: open
Precision class: ABEC-7
Preload: light (L)
Separator: phenolic
Arrangement: universally ground matched set, DT / DB / DF

Quantity and configuration

Supplied as a triplex set of single-row bearings ground to work together. Each bearing is a separate part; the grind is what makes the set.

Fitting notes

The set is assembled with its match marks aligned as ground, in the arrangement the machine calls for. Shaft and housing seats are held to the tolerance grade of the bearing, and clamp load passes through the ring faces rather than the separator. Preload comes from the flush-ground faces once the rings are clamped solid, so no shim stack is involved.

Interchange guidance

The 55 x 100 x 21 mm envelope matches the ISO 7211 series. New Departure Hyatt was a General Motors division and the line later passed through Delphi, so this designation is obsolete and is searched alongside its ISO number. A same-envelope bearing built to a different contact angle, preload class, separator material or set count is a related size rather than an interchange.