FafnirAAMM9111-2SMBRPrecision Spindle Ball Bearing – 35 mm Bore, 80 mm OD, 21 / 25 mm Width, Machined Bronze Cage, ABEC 7/9

Product Description

What this part is

Fafnir AAMM307-2-SMBR, a precision spindle ball bearing with a machined bronze cage on the 300 heavy series envelope. Bore Diameter: 35 mm. Outside Diameter: 80 mm. Overall Width: 21 mm at the inner ring, 25 mm across the outer ring. Rolling Elements: Ball. Number Of Rows: 1. Bore Type: Straight. Closure Type: Open. Cage Material: Bronze. Cage Type: Machined. Precision Class: ABEC 7/9 / P4S. Series: 300. Base Number: MM307.

Decoding the designation

MM — Fafnir super-precision spindle range, ground to ABEC 7/9 (P4S) tolerances.

307 — 300 heavy dimension series, bore code 07: a 35 mm bore in an 80 mm outside diameter.

MBR — machined bronze cage.

What these specs mean in practice

Cage Material: Bronze, machined rather than pressed. A machined bronze cage tolerates higher temperature and poorer lubrication than phenolic and holds ball spacing under shock, which is why it is specified on spindles that see intermittent or marginal lubrication. Precision Class: ABEC 7/9 / P4S holds bore, outside diameter and running accuracy to super-precision limits. The two width figures describe a stepped construction: the rings are not flush, so the 21 mm dimension sets the shaft clamp length and the 25 mm dimension sets the housing bore length.

Quantity and configuration

Unit Quantity: 2 Pcs. Two bearings ship together.

Interchange guidance

The bore and outside diameter match the ISO 307 envelope, 35 x 80 mm, but the stepped 21 / 25 mm width is a special execution and no ISO number carries it, so no like-for-like interchange is published here rather than naming a part that would not fit. Timken MM307K and MM307WI share the 35 x 80 mm envelope at 21 mm flush width. Searchable variants include AAMM307-2-SMBR, AA-MM-307-2-SMBR, AA MM 307 2 SMBR, MM307MBR and MM307.