NDHPrecision Angular Contact Ball Bearings 30x62x16 mm, Tandem (DT) Ground, Light Preload, ABEC 7 — 15 Pcs

Product Description

What this part is

NDH Q20206DT precision angular contact ball bearings, each 30 mm bore x 62 mm outside diameter x 16 mm wide — the 7206 envelope. These are single-row bearings ground to be mounted in tandem, not double-row bearings. That distinction changes how you clamp and preload the stack, so it is the first thing to check against your drawing.

Decoding the designation

Q — NDH precision (quality-ground) angular contact prefix.

202 and 06 — 200-series envelope, bore code 06, giving a 30 mm bore and the standard 7206 envelope of 30 x 62 x 16 mm.

DT — duplex tandem: bearings ground as a set to sit with their contact lines facing the same direction, so the rows share thrust in one direction.

L — light preload.

7 — precision class ABEC 7.

What these specs mean in practice

Tandem is what you choose when thrust is heavy and one-directional. Both bearings’ contact lines point the same way, so axial capacity roughly doubles against a single bearing — but a tandem stack on its own cannot locate the shaft in the opposite direction. It needs an opposing bearing somewhere in the arrangement or the shaft floats one way. Back-to-back (DB) and face-to-face (DF) sets, by contrast, take thrust both ways from one pair. Fit a tandem set where the drawing calls for DB or DF and you either lose axial location or preload the spindle to death, even though the envelope is identical.

Light preload keeps heat generation and power draw down while still eliminating axial play, which suits higher-speed spindles better than a medium or heavy preload. ABEC 7 controls bore, outside diameter, width and, critically, radial and axial runout, so the rings can be fitted in any rotational orientation without hunting a high spot.

Published dimensions

Bore (d): 30 mm

Outside diameter (D): 62 mm

Width (B): 16 mm per bearing, 32 mm for a clamped tandem pair

Rows: 1 per bearing

Precision: ABEC 7

Preload: light

Arrangement: DT, duplex tandem, universally ground

Closure: open, no seals or shields

Quantity and configuration

This listing supplies 15 pieces. Each piece is one complete single-row bearing, ground to the DT tandem specification so it can be stacked with its fellows. Keep any bearings that arrive marked as a set together and in the orientation supplied — the set accuracy comes from the matched face grind, and reversing or mixing rings destroys it.

Fitting notes

Press or heat — never drive an ABEC 7 bearing onto a shaft. Clamp the inner rings fully against each other and against the shaft shoulder, and clamp the outer rings equally in the housing; a partially clamped set never develops its designed preload. Confirm the machine’s bearing arrangement drawing actually calls for tandem before fitting. Grease sparingly, roughly a quarter to a third fill, or use the oil-air system the spindle was built around.

Interchange guidance

NDH (New Departure Hyatt) was a General Motors / Delco bearing division and is long obsolete, so buyers normally arrive here from a current designation. Same-envelope 30 x 62 x 16 mm precision angular contact equivalents: NSK 7206A5TYNDTP4 (A5 is NSK’s 25° code) and 7206CTYNDTP4 (C is 15°), SKF 7206 ACD/P4ADT (AC is 25°), FAG B7206-E-T-P4S-DT (E is 25°), NTN 7206CT1DTP4 (C is 15°), and Fafnir/Timken 2MM206WICRDT at 15° or 3MM206WICRDT at 25°. Match the contact angle and the arrangement code, not just the dimensions — DT, DB and DF are not interchangeable. The 2MM206WICRDUL reading that has travelled with this record names a light-preload duplex pair rather than a tandem set, so it is carried as a search term with that difference stated.