FAG618052ZThin Section Deep Groove Ball Bearing 25x37x7 mm, Two Steel Shields, 61805 / 6805 Series

Product Description

What this part is

A FAG 61805-2Z thin section single-row deep groove ball bearing — 25 mm bore, 37 mm outside diameter, 7 mm width — with a steel shield on each face. The 61800 series carries a very small cross-section for its bore, which is what lets a designer put a bearing into a thin-walled hub, a compact gear train or a robot joint where a standard 6205 would not fit.

Decoding the designation

61805 – thin section single-row deep groove ball bearing, 25 mm bore, 37 mm OD, 7 mm width; also written 6805
2Z – two steel shields, one on each face, non-contact
No clearance suffix, so internal clearance is normal (CN)

What these specs mean in practice

A thin section bearing gives up load capacity to save space: the 6 mm wall between bore and outside diameter is roughly half that of a standard series bearing of the same bore, so shaft and housing seats must be accurate and well supported. Because the rings are thin they conform to their seats, and an out-of-round housing bore transfers straight into the raceway. Steel shields are non-contact, so they retain grease and exclude coarse debris while adding almost no friction and keeping speed capability high. For fine dust or damp service a contact-sealed version is the better choice.

Published specifications

Bore: 25 mm (0.9843 in)
Outside diameter: 37 mm (1.4567 in)
Width: 7 mm (0.2756 in)
Radial cross-section: 6 mm per side
Rows: 1
Rolling elements: balls
Closure: two steel shields, non-contact
Internal clearance: CN (normal)
Lubrication: grease filled behind the shields
Material: through-hardened bearing steel

Quantity and configuration

Sold as 1 Pc, one complete bearing with both shields fitted. No snap ring, spacer, seal or preload washer is included.

Fitting notes

Mounting force is applied to the ring being fitted, never through the balls, and the shields are not a press surface. Thin rings distort readily, so the shaft and housing seats want to be round, square and within tolerance, and the bearing is pressed square rather than cocked. Grease sits behind the shields and a relubrication port in the housing has no path into the bearing.

Interchange guidance

The direct equivalent is a double-shielded thin section bearing in the 25 x 37 x 7 mm envelope: SKF 61805-2Z, NSK 6805ZZ, NTN 6805ZZ, Koyo 6805ZZ, Nachi 6805ZZ. Contact-sealed versions such as 61805-2RS and 6805-2RS share the envelope but rub on the inner ring and run at lower speed, and an open 61805 has no closure, so those are related versions rather than equivalents. A 6005 standard-series bearing in the same 25 mm bore is 47 mm OD and 12 mm wide and is not an interchange.