NHBBSuper-Precision Angular Contact Ball Bearing Matched Duplex Pair, 45 x 75 x 16 mm, Light Preload, Phenolic Cage, 2 Pieces per Set

Product Description

What this part is

A factory matched duplex pair of super precision angular contact ball bearings, supplied as one set of two. Each bearing measures 45 mm bore, 75 mm outside diameter and 16 mm width, corresponding to the ISO 7009 envelope. Both rings are engraved ME-1109DL and THRUST NHBB USA, and both carry the asterisk match mark and a scribed match line across the outside diameter that identify them as a ground-together set.

Decoding the designation

NHBB is New Hampshire Ball Bearings.

ME- is NHBB’s precision spindle bearing series prefix.

1109 is the NHBB size code corresponding to the 7009 envelope, 45x75x16 mm.

DL denotes duplex, light preload.

THRUST engraved on the outer ring face is the thrust direction marking, identifying which way the bearing takes axial load.

Quantity and configuration

One lot containing two bearings. DL means duplex, and NHBB ground these two rings as a matched set, so they are inventoried and sold as a single unit. The bearings are stacked in one sealed bag under a single paper band marked NHBB ME1109DL, both engraved ME-1109DL, each with an asterisk match mark and a scribed V line that aligns across the pair.

The two bearings belong together. The preload the set produces depends on the two rings having been finished as a couple, so a half of this set mated with a bearing from another set no longer produces the specified preload. This listing is not suitable where only one bearing is required.

Why a duplex universal grind is worth paying for:
On an ordinary pair of precision bearings, setting preload is a metrology job: measure, then shim or grind a spacer until the clamped stack produces the axial stiffness the design calls for. A universally ground duplex set removes that step. The ring faces are finished so that clamping the two together back-to-back, face-to-face or in tandem produces the specified light preload on its own, repeatably across rebuilds.

Preload class matches across the set, which is why DL appears on both rings. A light preload bearing mated with a medium or heavy one loads the two rows unevenly: one row carries more than its share, runs hotter, and fails first. Light preload is the choice for speed and thermal stability, trading some axial rigidity for lower friction and less heat generation than a medium or heavy setting.

What these specs mean in practice

The cages are phenolic, visible in the photographs as the dark reddish-brown rings between the raceways. Laminated fabric is far lighter than steel or brass, so cage inertia and ball pocket friction stay low, and phenolic absorbs oil, which carries the bearing through start-up and marginal lubrication. The constraint is temperature: sustained running should stay below roughly 120 °C.

The 16 mm width at 45 mm bore puts this in the light 70xx section, the conventional choice for a high-speed spindle where the radial envelope is constrained and loads are moderate.

Mounting data

Universally ground duplex; mounts back-to-back, face-to-face or in tandem to the specified light preload. Outer rings carry an engraved THRUST marking indicating the axial load direction, and asterisk match marks with a scribed V line spanning the pair.

Interchange guidance

The metric equivalent designation for this size and configuration is 7009-C-TPA-P4-DUL, a 45x75x16 mm super precision angular contact bearing with a phenolic cage, P4 precision and duplex light preload. Any maker’s 7009 in a universally ground light preload duplex configuration is worth evaluating, but contact angle, cage material and preload class should be confirmed, and the replacement should be a matched pair rather than two singles. Matching the boundary dimensions alone is never sufficient on a spindle bearing.