NDHQ20208DTL7AAngular Contact Ball Bearing 40 x 80 x 18 mm, Flanged Outer Ring, Tandem Duplex

Product Description

What this part is

An NDH Q20208-DT-L7A angular contact ball bearing with a flanged outer ring — 40 mm bore, 80 mm outside diameter, 18 mm wide, tandem duplex matched. The envelope is the ISO 7208 size.

Decoding the designation

Q20208 — NDH’s angular contact ball bearing series, 40 mm bore; the 40 × 80 × 18 mm envelope corresponds to an ISO 7208
DT — duplex tandem: two rows arranged facing the same direction
Flanged outer ring — the outside diameter carries an integral locating flange
L7A — NDH internal suffix, carried as a searchable designation

What these specs mean in practice

An angular contact ball bearing carries thrust in one direction, because the ball-to-raceway contact line runs at an angle across the bearing and can only be pushed, never pulled. A tandem arrangement faces both rows the same way, so the two rows share one thrust load and roughly double the axial capacity in that single direction — which is the difference from a back-to-back or face-to-face duplex, where the rows oppose each other and take thrust both ways. The ISO 7208-C equivalent puts the contact angle at 15°, a shallow angle that favours speed and radial capacity over pure thrust. The flanged outer ring locates the bearing axially against a machined housing face rather than needing a shoulder bored into the housing, which shortens the housing and fixes the axial position without shims.

Published specifications

Bore: 40 mm
Outside diameter: 80 mm
Width: 18 mm
Rolling element: ball
Arrangement: duplex tandem (DT), rows facing the same direction
Axial capacity: one direction, shared across both rows
Outer ring: flanged
ISO envelope equivalent: 7208 (7208-C, 15° contact angle on the ISO scheme)
Closure: open

Quantity and configuration

1 Pc. Thirty-six pieces are in stock from the same lot.

Interchange guidance

The ISO envelope is 7208, so 7208-C, SKF 7208 BECBP, FAG 7208-B-XL-TVP and NSK 7208A are the same 40 × 80 × 18 mm size. Those are related sizes rather than equivalents: none of them carries the flanged outer ring, and the B / A designations are 40° and 30° angles against the 15° implied by the 7208-C reference, which changes the thrust-to-speed balance entirely. A Q20208-DB or -DF in the same NDH series is back-to-back or face-to-face and takes thrust in both directions, so it is a different part.