Fafnir3MM9107WIDULSuper-Precision Angular Contact Ball Bearing 35x62x14 mm 25 Degree Duplex Matched Pair Light Preload ABEC 9

Product Description

What this part is

A super-precision angular contact ball bearing in the Fafnir WI spindle series, supplied as a factory-matched duplex pair. Bore 35 mm, outside diameter 62 mm, width 14 mm per bearing.

Decoding the designation

3MM — 25° contact angle in the Fafnir scheme. A 2MM prefix on the same envelope would be 15°.
9107 — the leading 9 marks the ISO 70 light series; the size corresponds to a 7007, at 35 mm bore and 62 mm outside diameter.
WI — super-precision spindle bearing series.
DUL — duplex universal pair, light preload.
The MM prefix carries the P4S class: ABEC 7 dimensional tolerances with ABEC 9 running accuracy.

What these specs mean in practice

A 25° contact angle carries appreciably more thrust and delivers greater axial stiffness than the 15° variant of the same envelope, in exchange for a lower speed limit and more heat generation. Light preload keeps friction and temperature rise at the low end of the preload range while retaining the stiffness the 25° angle contributes, which is the usual choice for a spindle that has to hold position under cutting thrust rather than simply spin fast. P4S running accuracy at ABEC 9 is the tightest runout grade Fafnir published for this series.

Quantity and configuration

2 Pcs — one matched duplex pair. Universal grinding allows the pair to be assembled back-to-back, face-to-face or in tandem.

Fitting notes

The preload is ground into the ring faces and is realised only when both inner rings and both outer rings are clamped solidly against their seats. Alignment marks on the outer ring faces set the intended arrangement.

Interchange guidance

The ISO shorthand for this size and angle is 7007 AC, and the designation appears as 7007 A or 7007 E in some schemes. Same-envelope bearings at a 15° contact angle, such as a 2MM9107WI, or at medium or heavy preload, are related sizes rather than interchanges. A 3MM207WI is the heavier 72-series section on the same 35 mm bore, not a substitute.