FafnirMM205K-CRSpindle Deep Groove Ball Bearing – Straight Bore, 25 mm ID, 52 mm OD, 15 mm Width, Open, ABEC 7/9, Machined Phenolic Cage

Product Description

What this part is

Fafnir MM205K-CR precision spindle deep groove ball bearing. Brand: Fafnir. Manufacturer Part Number: MM205K-CR. Bearing Type: Deep groove ball bearing, spindle quality. Series: 200K. Base Number: MM205K. Bore: 25 mm. Outside Diameter: 52 mm. Width: 15 mm. Bore Type: Straight. Closure Type: Open. Number of Rows: 1. Rolling Elements: Ball. Bearing Material: Chrome steel. Design Units: Metric. Country of Origin: United States.

Decoding the designation

Precision Class: ABEC 7/9, from the MM prefix. Cage Material: Phenolic. Cage Type: Outer-ring land-riding, machined, from the CR suffix. The 200K series is Fafnir’s spindle deep groove family: a single row of balls in a deep radial groove, ground to super-precision tolerances and cages, and running on a radial contact rather than an angular one.

What these specs mean in practice

A deep groove raceway takes radial load and thrust in both directions from one bearing, so it does not need a matched opposing bearing to locate a shaft the way an angular contact set does. ABEC 7/9 tolerances hold the running accuracy a grinding or milling spindle needs. Cage Material: Phenolic — light, self-lubricating and quiet, which is what carries the speed rating on a spindle-quality bearing. Lubricant: grease or oil.

Quantity and configuration

Unit Quantity: 1 Pc. A single bearing, complete with inner ring, outer ring, ball complement and cage.

Interchange guidance

Envelope Equivalent: ISO 6205, which shares the 25 x 52 x 15 mm boundary dimensions. A standard-tolerance 6205 is a dimensional match and a precision downgrade, so it substitutes on fit and not on running accuracy. MPN Variants: MM205K-CR, MM205KCR, MM 205 K CR, MM205K CR, 205K.