NDHQ20214DTT7AAngular Contact Ball Bearing Tandem Duplex Set 70x125x24 mm ABEC-7 Heavy Preload Phenolic Separator

Product Description

What this part is

New Departure Hyatt Q20214DTT7A single-row angular contact ball bearing, 70 mm bore, 125 mm outside diameter, 24 mm width. Open on both faces, phenolic ball separator, faces flush ground for duplex tandem mounting.

Decoding the designation

Q – nonmetallic (phenolic) ball separator
20214 – New Departure 20200 angular contact series; bore code 14 = 70 mm; ISO 7214 dimensional envelope
DT – duplex tandem set, all faces flush ground to preload requirement for universal mounting in tandem, back-to-back or face-to-face
T – heavy preload
7 – ABEC-7 tolerance class
A – rust-preventive slush

What these specs mean in practice

Heavy preload is the top of the three NDH duplex classes — L light, X medium, T heavy. It gives the highest axial and radial stiffness and the tightest axial position control, at the cost of running torque, heat and speed ceiling, which places heavy-preload sets in boring, grinding and heavily loaded spindle positions. Tandem rows carry thrust in the same direction and share it, roughly doubling one-direction axial capacity over a single bearing.

Published specifications

Bore: 70 mm (2.7559 in)
Outside diameter: 125 mm (4.9213 in)
Width, each bearing: 24 mm (0.9449 in)
Rows: 1 per bearing
Rolling element: ball
Closure: open
Precision class: ABEC-7
Preload: heavy (T)
Separator: phenolic
Arrangement: duplex tandem, universally ground

Quantity and configuration

2 Pcs, one matched tandem set of single-row bearings. A DT designation is a matched set, not a double-row bearing.

Fitting notes

Match marks on the ring faces are aligned as ground when the set is stacked. 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.

Interchange guidance

The 70 x 125 x 24 mm envelope matches the ISO 7214 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 New Departure Hyatt was a General Motors division and the line later passed through Delphi, so this designation is obsolete and is searched alongside its ISO number.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 or separator material is a related size rather than an interchange.