RHPLJ-1-1/8Imperial Open Deep Groove Ball Bearing, 1-1/8 x 2-1/2 x 5/8 in, Light Series, Normal Clearance, Pressed-Steel Cage

Product Description

What this part is

A single-row deep groove (radial) ball bearing from RHP’s imperial LJ light series, sized in inches rather than millimetres: 1-1/8 in bore, 2-1/2 in outside diameter, 5/8 in width. In metric terms that is 28.575 x 63.500 x 15.875 mm, close to a metric 6206 but not equal to it. This is the open configuration: no shields, no seals, both faces of the ball complement exposed.

Deep groove ball bearings carry radial load plus moderate axial load in either direction and tolerate high speed. The LJ series is the inch counterpart to the metric 60xx/62xx light series.

Reading an RHP imperial number

RHP’s inch-series radial ball bearing code reads prefix, then bore, then variant suffixes. LJ: light series single-row radial ball bearing, J for ball journal, RHP’s traditional term for a radial ball bearing. 1-1/8: the bore, stated directly as an inch fraction; RHP writes this as LJ1.1/8, and LJ-1-1/8 and LJ1-1/8 are the same bearing. No closure suffix: open.

Neighbouring codes in the same family: -2RS or -2RSJ is rubber contact seals both sides, greased for life, with better exclusion, more friction and a lower speed ceiling. -ZZ or -2Z is steel shields both sides, and a single Z is one shield only. A trailing J (LJ1.1/8J) is a cage code, denoting a pressed-steel, rolling-element-centred cage, which is the standard cage in this size, so LJ1-1/8 and LJ1.1/8J describe the same open bearing. XLJ is extra light, MJ medium and HJ heavy, all with different outside diameters and widths on the same bore; MJ1-1/8 is 2-13/16 in OD x 13/16 in wide. KLNJ is a small radial ball journal built to BS292 Part 2 standard limits, a different tolerance and section scheme. C2, CN, C3 and C4 are radial internal clearance codes; CN is normal and carries no marking, so an unsuffixed LJ number is a normal-clearance bearing.

What these specs mean in practice

Open means the bearing has no built-in grease charge and no barrier. That suits an oil-splash or oil-mist gearbox, a circulating-oil headstock and a line-shaft hanger with a grease nipple. Lubricant flows through the bearing, carrying heat and debris out with it.

Normal (CN) radial internal clearance suits a normal shaft and housing fit at moderate temperature. Under a heavy interference shaft fit, or where the inner ring runs appreciably hotter than the housing, the bearing loses clearance in service and C3 covers that condition.

Published ratings

Bore: 1.1250 in (1-1/8 in) / 28.575 mm. Outside diameter: 2.5000 in (2-1/2 in) / 63.500 mm. Width: 0.6250 in (5/8 in) / 15.875 mm. Basic dynamic load rating Cr: 20,200 N (20.2 kN), per bearing. Basic static load rating C0r: 11,300 N (11.3 kN), per bearing. Limiting speed: 11,700 rpm on grease, 15,500 rpm on oil. Radial internal clearance: CN (normal, unmarked). Rows: 1. Rolling elements: balls. Cage material: pressed steel. Cage type: rolling-element centred. Mass: 0.219 kg (0.483 lb). Precision class: ISO Normal / ABEC 1. Country of origin: United Kingdom.

The load ratings, limiting speeds and mass above are the RHP/NSK catalogue figures for the LJ1.1/8 envelope. SKF’s dimensionally identical RLS 9 is published at Cr 20.3 kN and C0r 11.2 kN, an internal-geometry difference between the two makers, and either bearing is a valid replacement for the other.

Quantity and configuration

Each unit is one bearing, open and loose. Unit Quantity: 1 Pc.

Mounting data

Bore: 1.1250 in / 28.575 mm, for an inch shaft. The inner ring is the interference-fitted member in a rotating-shaft position.

Interchange guidance

RHP was absorbed into NSK and traded for years as NSK-RHP, so an RHP to NSK cross is the same product line under the surviving brand. The imperial LJ series is still catalogued.

The industry base number for this envelope is RLS9 (also written RLS 9), used by SKF and followed by most other makers, so RLS9 and LJ1-1/8 are two names for the same bearing. NKE also lists it as LJ1.1/8.

Numbers that resemble a match without being one: MJ1-1/8 / RMS9 is the medium series on the same bore but a larger OD and width; LRJA1-1/8J is an RHP cylindrical roller bearing sharing the 1-1/8 x 2-1/2 x 5/8 in envelope with different load, speed and axial behaviour; LJ1-1/8-2RS / RLS9-2RS1 and LJ1-1/8-ZZ / RLS9-2Z fit the same housing but are sealed and shielded respectively, a functional change rather than a like-for-like swap.