Fafnir9124KDDeep Groove Ball Bearing 120 x 180 x 28 mm, One Metal Shield, Conrad Non-Filling-Slot, Extra-Light Series

Product Description

What this part is

A Fafnir (now Timken) 9124KD single-row deep groove ball bearing, 120 mm bore × 180 mm outside diameter × 28 mm wide, with one pressed steel grease shield and the opposite face open. It is from the 9100 extra-light series, so it takes a large shaft in an unusually shallow cross-section. Made in USA. It is a deep groove bearing rather than an angular contact bearing, carrying radial load with modest thrust in either direction.

Designation breakdown

9100: Timken’s extra-light series. Bore code 24: 120 mm, 24 × 5. K: Conrad, non-filling-slot, construction with a high shoulder on both the inner and outer rings, which makes it a deep groove bearing and gives it thrust capacity in both directions. D: one steel-plate grease shield. Timken’s Fafnir lettering system reads “D — Steel Plate grease shield on one side of bearing” and “DD — Shields on both sides of bearing.”

Fafnir closure suffixes

Fafnir closure suffixes differ from the industry convention. In Fafnir’s scheme D is one shield and DD is two; P is one seal and PP is two; L and LL are one and two Mechani-Seals; R and RR are land-riding rubber seals; T and TT are felt seals. G is the Wireloc snap ring rather than a shield or a seal, so 9124KG is a snap-ring bearing and 9124KD is this one-shield bearing. Timken’s catalogue table for this size lists 9124KD, 9124P, 9124PP and 9124KG as available and shows no 9124KDD, a two-shield version of this bearing never having been offered.

Markings

The photographs show one face fully open, with the balls and the riveted two-piece pressed steel ribbon cage visible, and the opposite face closed by a plain pressed steel shield. The ring is etched FAFNIR 9124KD and MADE IN USA, and the carton label reads FAFNIR 9124KD USA. The ISO analogue is 6024Z, one shield, rather than 6024ZZ or 6024-2Z, which are two-shield bearings.

Specifications in application

The extra-light series keeps the outside diameter to 180 mm and the width to 28 mm at a 120 mm bore, where a standard 6200-series equivalent would be considerably fatter and heavier, so a large-diameter shaft runs in a compact housing. A thin section carries less than a medium series, so this is a bearing chosen for geometry first and load second. The single shield keeps coarse debris out of the ball track and holds grease in on the side facing the dirty end of the machine, while the open face allows relubrication in place and oil circulation from a shared sump. Contamination protection from both directions calls for 9124P or 9124PP with seals, a two-shield version of this part not existing.

Published ratings

From Timken (cad.timken.com, 9124KD record, and Ball Bearing Catalog 10734, 9124K row). Basic dynamic radial load rating C: 86,300 N (19,400 lbf). Basic static radial load rating C0: 73,100 N (16,400 lbf). Limiting speed: 2,000 rpm grease, 2,331 rpm oil. Bearing weight: 2.2 kg (4.9 lb). Bore tolerance: 120 mm, +0.000 / −0.020 mm. Outside diameter tolerance: 180 mm, +0.000 / −0.025 mm. Shield thickness: 3.05 mm (0.120 in). Rolling elements: steel balls. The printed catalogue gives the 9124K a static rating of 71,100 N (16,000 lbf) and an extended dynamic rating CE of 88,900 N (20,000 lbf); CE is an extended-life rating rather than the conventional ISO 281 basic dynamic rating, so the CAD portal figures are the ones published above.

Condition

New old stock. The bearing has never been installed and spins freely, with grease stains and light handling marks on the rings visible in the photographs. It comes with its original plain brown carton, marked 1 EA, 321-001-0020 and 1D-39-F2 with a small FAFNIR 9124KD USA label; the first two are a distributor or end-user stock number rather than Timken part numbers.

Mounting data

Shaft backing shoulder diameter: 130 mm (5.1181 in). Housing backing shoulder diameter: 169.90 mm (6.6890 in). Maximum shaft fillet radius: 2.0 mm (0.079 in). Shield thickness: 3.05 mm (0.120 in). Snap-ring groove outside diameter 192.9 mm with a 6.63 mm (0.261 in) offset applies to the 9124KG variant, not to this bearing.

Interchange guidance

The 120 × 180 × 28 mm envelope is the ISO 6024 boundary set, so 6024-series deep groove bearings from any maker fit the same shaft and housing, and 6024Z, one shield, is the matching closure analogue, for example SKF 6024-Z, FAG 6024.Z, NSK 6024Z or NTN 6024Z. 6024ZZ, 6024-2Z and 6024-2RS are two-closure bearings and are not equivalent to a 9124KD. Related Fafnir variants at this size: 9124K open, 9124KG with a Wireloc snap ring, 9124P one seal, 9124PP two seals. Fafnir is a retired brand absorbed into Timken.