FAG618/670-MA-C3Single-Row Deep Groove Ball Bearing 670 x 820 x 69 mm, Machined Brass Cage, C3 Increased Clearance, Open

Product Description

What this part is

A FAG 618/670-MA-C3 single-row deep groove ball bearing: 670 mm bore, 820 mm outside diameter, 69 mm width. One complete non-separable bearing, both rings, the full ball complement and the machined brass cage assembled. It sits in FAG’s 618 dimension series, a thin-section large-diameter family: 75 mm of radial wall for a bore of two-thirds of a metre. Bearings in this range go into large rotating structures — turntables, kilns and dryer supports, large fan and blower shafts, tunnelling and mining machinery, mill and pulley positions where the shaft diameter is set by strength and stiffness rather than by load.

Decoding the designation

618: FAG deep groove ball bearing dimension series 18, an extra-thin section for very large bores. /670: bore diameter in millimetres, 670 mm; the slash form is used where the bore is not a standard series step. MA: machined brass solid cage, outer ring guided. C3: radial internal clearance greater than the normal group.

Specifications

Manufacturer: FAG (Schaeffler). Part Number: 618/670-MA-C3. Base Number: 618/670. Bearing Type: single-row deep groove ball bearing. Series: 618, deep groove ball dimension series 18. Bore: 670 mm (26.378 in). Outside Diameter: 820 mm (32.283 in). Width: 69 mm (2.717 in). Bore Type: straight. Number of Rows: 1. Rolling Elements: steel balls. Cage Type: machined solid, outer ring guided. Cage Material: brass. Internal Clearance: C3. Closure Type: open, both sides. Precision Class: ABEC 1 / P0. Basic Dynamic Load Rating (Cr): 442 kN. Basic Static Load Rating (C0r): 1,000 kN. Reference Speed: 1,300 rpm. Limiting Speed: 1,100 rpm. Lubricant: grease or oil. Bearing Material: through-hardened bearing steel. Mass: 77.5 kg (170.9 lb). Maximum Temperature: 120 °C. Minimum Temperature: -30 °C. Design Units: metric. Harmonization Code: 8482.10.50.68. GTIN: 4012801623506. Country of Origin: Romania.

What these specs mean in practice

The thin 618 section is what makes this bearing possible at all at 670 mm bore. It keeps the outside diameter and the mass manageable, which in turn keeps the housing and the surrounding structure buildable. A thin ring takes its stiffness from the seat it runs in, so the design assumes a continuous, accurately machined housing bore over the full circumference.

The machined brass cage is the correct choice at this diameter. Solid brass holds its geometry where a pressed steel or polyamide cage in a ring this large would flex and fatigue, it tolerates elevated temperature, and outer ring land guiding keeps it running concentrically rather than being pushed around by the balls.

C3 clearance is specified where the inner ring is fitted with a heavy interference fit, where the inner ring runs hotter than the outer, or both — conditions that consume internal clearance in service, so the bearing starts looser and reaches its working clearance hot.

Quantity and configuration

Unit Quantity: 1 Pc. One complete bearing, open on both sides. Both rings, the full ball complement and the brass cage are supplied as a single non-separable assembly.

Interchange guidance

Direct equivalents in other catalogues use the same ISO base number: SKF 618/670 MA/C3, NSK 618/670 and NTN 618/670 in a comparable cage and clearance execution. Within FAG, 618/670-M-C3 is the pressed-cage execution and 618/670-MA is the same brass-cage bearing in normal clearance. On a bearing this large the cage material and the clearance group are the two variables that differ most often between suppliers.