NDHH20206DTL5Matched Tandem Set, Angular Contact Ball Bearings 30 x 62 x 16 mm, 15 Degree Contact Angle, ABEC 5, Open, 2 Pcs

Product Description

What this part is

A matched tandem set of two New Departure Hyatt angular contact ball bearings in the 7206 envelope — 30 mm bore, 62 mm outside diameter, 16 mm width per bearing. Open, 15° contact angle, ABEC 5 precision. Both bearings are ground together as one set to sit side by side facing the same way, which roughly doubles the thrust capacity available in a single-direction position. New old stock American spindle-grade product.

Decoding the designation

20206 — NDH’s number for the ISO 7206 size, 30 x 62 x 16 mm. The 20-series prefix is the 15° angular contact family; the 30-series is the steeper 40° build.
H — NDH ring and grinding variant prefix.
DT — duplex tandem. Two separate single-row bearings, ground as a matched set to be mounted facing the same direction. This is not a double-row bearing.
L5 — NDH tolerance grade, equivalent to ABEC 5.

What these specs mean in practice

A tandem arrangement is the answer when thrust in one direction exceeds what a single bearing will take. Both bearings face the same way, so they share the axial load roughly equally instead of one carrying all of it — capacity goes up, but only in that one direction, so the assembly still needs something opposing at the other end of the shaft. It is the opposite trade from a back-to-back pair, which handles thrust both ways and resists moment loads but adds no capacity in either direction. The 15° contact angle keeps ball loading close to radial, which limits heat and favours speed, giving up thrust capacity against a 40° build — and the tandem pairing is precisely how you recover that thrust capacity without giving up the speed. ABEC 5 running accuracy is a real step above standard: tight enough for a working spindle, and it demands that shaft and housing seats be ground and true to suit or the tolerance is wasted.

Quantity and configuration

2 Pcs — a matched tandem set of two bearings, ground together and shipping together. They are not two independent bearings; splitting the set loses the matching.

Fitting notes

Both bearings go in facing the same direction, with the wide land of each outer ring toward the thrust. Fitting one reversed converts the set into a back-to-back pair with entirely different load behaviour and no shared thrust capacity. Look for the grinding marks across the ring faces — usually a scribed line or V — and line them up on assembly, because that is how the set was ground. Seats must be clean, ground and burr-free, and interference fit adds to whatever internal preload the set carries, so check sizes against the drawing. Never press through the ball complement. Lubricate sparingly with a spindle grease or run oil-air.

Interchange guidance

New Departure Hyatt was General Motors’ bearing division and is long out of production, so cross-reference by the ISO number: 7206 at 15°, supplied as a tandem duplex set. Genuine same-angle equivalents include SKF 7206 CD/P4ADT, FAG B7206-C-T-P4S-DT, NSK 7206C in a DT set and Fafnir/Timken 2MM9106WI CR DT. Related sizes fill the identical 30 x 62 x 16 mm envelope at other contact angles — 7206AC is 25°, 7206B is 40°, and NDH’s own 30206 is the 40° version of this number. Those are different parts, not substitutes. The arrangement code matters just as much: a DB or DF pair of the same size handles thrust in both directions instead of doubling it in one, and will not do this job.