NSK7000A5TYDULPA1Miniature Super Precision Angular Contact Ball Bearing Matched Pair 10 x 26 x 8 mm, 25° Contact Angle, ABEC 7 Class, Polyamide Cage, Duplex Light Preload, 2 Pieces

Product Description

What this part is

A matched pair of super precision angular contact ball bearings in the 7000 envelope — 10 mm bore, 26 mm outside diameter, 8 mm width per bearing. This is the small end of the spindle bearing range: the size that goes into high-speed auxiliary spindles, instrument drives, small rotary axes and precision small gearheads. Universally ground and supplied as a duplex set with light preload built in.

Decoding the designation

7000 — ISO boundary dimensions in the thin 70xx dimension series: 10 x 26 x 8 mm.
A5 — 25° contact angle in NSK nomenclature. This distinction is worth spelling out, because NSK uses a bare A for 30° and C for 15°: 7000A and 7000A5 are not the same bearing.
TY — polyamide (nylon) cage.
DUL — duplex, universally ground, light preload.
PA1 — NSK precision and execution code, carried here as a searchable reference; the governing precision class is ABEC 7.

What these specs mean in practice

A 25° contact angle is the middle setting in the spindle range. Against a 15° bearing it takes substantially more thrust and gives a stiffer axial response; against a 30° bearing it runs faster and generates less heat. Light preload is the high-speed choice — less internal friction, less heat, higher permissible rpm, at the cost of some stiffness. At a 10 mm bore that combination is nearly always the right one, because bearings this small are almost always chosen for speed and positional accuracy rather than load.

The polyamide cage is the low-friction, low-noise option. It weighs very little, so it loads itself hardly at all under centrifugal force, and it runs quietly. The limitation is temperature: polyamide will not tolerate sustained high heat, so lubrication needs to be clean, the grease fill light and the operating temperature kept moderate. Where a spindle runs hot continuously, a phenolic or metal cage version of the same bearing is the better choice.

Quantity and configuration

This listing is a set of 2 pieces — a duplex pair ground together. Universal grinding means you can stack them back to back (DB) for maximum moment stiffness and thrust in both directions, face to face (DF) where the housing bores may be slightly misaligned, or in tandem (DT) to double thrust capacity in one direction. Clamping the pair between the shaft shoulder and the locknut develops the built-in light preload; adding a spacer changes the preload and defeats the matching.

Fitting notes

Bearings this small are easy to destroy during assembly and hard to inspect afterwards. Hold shaft journal and housing bore runout and roundness to a few microns and keep the abutment faces square. Mount with a proper arbor or small press that loads only the ring being fitted — on an 8 mm wide bearing it takes almost nothing to drive force through the balls and brinell the raceways, and the damage will not be visible. Keep the pair oriented as marked; reversing one bearing changes the preload. Grease sparingly with a light spindle or instrument grease; over-filling a 10 mm preloaded pair will heat it up long before it reaches its rated speed. Tighten the locknut to a controlled figure rather than by feel.

Interchange guidance

The cross-references on this listing are unusually clean, and all three name the same 25° contact angle: 7000E is the RHP form (RHP E is 25°), B7000E is the FAG spindle-series form (FAG E is also 25°), and 3MM9100WI-CR-DUL is the Fafnir/Timken form (the Fafnir 3MM prefix is 25°, 9100 is the 7000 envelope, CR is a phenolic outer-land cage and DUL matches the duplex light preload). All are genuine equivalents rather than merely dimensional matches. SKF’s equivalent is 7000 ACD/P4ADGA, where AC is 25°. The 15° version of the same envelope is 7000C or Fafnir 2MM9100WI, and the 30° version is 7000A — same dimensions, different contact angle, and not substitutes inside an existing preloaded pair.