NSK7007A5TYDUMSuper Precision Angular Contact Ball Bearing Matched Pair 35x62x14 mm 25° Polyamide Cage Medium Preload

Product Description

What this part is

A duplex-ground matched pair of single-row super-precision angular contact ball bearings. Each bearing is 35 mm bore, 62 mm outside diameter, 14 mm width, ground to a 25° contact angle and a medium preload band, with a polyamide cage. The pair clamps as one unit at 28 mm total width.

Decoding the designation

The 70 prefix and bore code 07 give ISO dimension series 70 at a 35 mm bore. In the NSK scheme A5 is a 25° contact angle — distinct from A at 30° and C at 15°. TY is a ball-guided polyamide cage rated to a 120 °C ceiling, DU duplex universal grinding and M the medium preload grade. The alternate carton number 7007E uses the RHP and Timken angle letter E, also 25°, confirming the angle from a second designation.

What these specs mean in practice

A 25° contact angle is the thrust-biased choice in this envelope. Axial capacity and axial stiffness both rise with contact angle, so a 25° pair holds a spindle’s axial position harder under cutting thrust than the 15° version of the same size. The cost is speed: the steeper load line increases ball centrifugal and gyroscopic effects, lowering the limiting speed and adding heat at equal duty.

A polyamide cage is the quiet, low-friction option and it is the spec that separates this bearing from the phenolic-caged TR variants in the same family. Polyamide is light and self-lubricating against the balls, tolerates momentary lubrication starvation better than steel, and damps cage noise. Ball guidance rather than land guidance keeps the cage centred by the ball set itself. The trade is the temperature ceiling: polyamide is limited to roughly 120 °C and, unlike phenolic or steel, it is degraded by long exposure to hot oil, which makes cage material a real selection criterion rather than a detail.

Medium preload sits between the light and heavy grades. Preload removes internal play, fixes the contact angle and makes axial position and runout repeatable; the friction it adds becomes heat that shifts the preload as the spindle warms. The M grade buys more axial and radial stiffness than L at the cost of more heat, suiting a spindle carrying real cutting load rather than one chasing maximum speed.

Quantity and configuration

Matched pair, 2 Pcs, duplex ground as one set.

Fitting notes

The pair is assembled in the orientation its face marks indicate, most often back-to-back for moment stiffness, and the inner rings are clamped solid against one another so the ground relief sets the preload. A duplex set behaves as a single bearing, and its preload band of a few microns belongs to that specific pair. Shaft and housing seats at this class are ground and measured. Mounting heat is worth watching on a polyamide-caged bearing, since induction heating a ring well past the cage’s temperature limit damages the cage rather than the steel.

Interchange guidance

7007E is the same bearing under the RHP and Timken angle scheme, and 3MM9107WI is the Fafnir-scheme number for the same 25° 70-series size. Same-envelope bearings differing in contact angle, cage, preload grade or tolerance class — 7007C at 15°, 7007A at 30°, the phenolic-caged TR variants, and the light and heavy preload grades — are related sizes rather than interchanges. A single universally ground bearing of this size is a different item, since SU pieces are not ground to this pair’s stack height.