McGillWide Inner Ring Ball Bearing Insert, 1-1/4″ Bore, 2.8346″ Cylindrical OD, Setscrew Locking, Snap Ring Included

Product Description

What this part is

A McGill ER20 mounted-bearing insert — a single-row ball bearing with a wide inner ring extended both sides, a cylindrical outer ring, contact seals and a flinger, locked to the shaft by setscrews in the extended inner ring. The supplied snap ring drops into the groove in the outer ring to locate the bearing axially in a housing bore or a cast frame.

Decoding the designation

ER – McGill’s setscrew-locking insert series with a cylindrical (not spherical) outer ring
20 – bore in sixteenths of an inch: 20/16 = 1-1/4 in
Envelope corresponds to the industry ER207-20 / SER207-20 pattern, 72 mm nominal OD

What ships and what does not

This is the insert on its own, with its snap ring. There is no pillow block, no flange housing, no take-up frame and no eccentric collar. If you need a mounted unit, this is the bearing that goes inside one — buy the housing separately or reuse the housing already on the machine.

Published specifications

Bore: 1-1/4 in
Outside diameter: 2.8346 in (72 mm nominal)
Overall width across the extended inner ring: 1.689 in
Outer ring width: 0.937 in
Outer ring form: cylindrical, with snap ring groove
Snap ring: included
Locking: setscrews in extended inner ring
Seals: contact seals plus flinger
Material: 52100 bearing steel · Duty class: medium
Rows: 1, ball

What these specs mean in practice

A cylindrical outer ring is the important detail here. Unlike a spherical-OD insert, an ER does not self-align in its housing — alignment has to come from the housing bore, so the bore must be reasonably concentric and square to the shaft. In exchange the ER seats in a straight bore, which suits machined frames, gearcase walls and cartridge bores where a spherical seat is neither available nor wanted.

The snap ring sets the axial position. Fit it on the side you want to react thrust against, and remember that an ER with its snap ring becomes a locating bearing; leave the far bearing free to float or the shaft will bind as it warms. Setscrew locking is quick and serviceable, marks the shaft, and prefers steady unidirectional load over heavy reversing duty. Contact seals and the flinger handle dust and splash, not wash-down.

Quantity and configuration

One insert with one snap ring.

Fitting notes

Measure the housing bore against the 2.8346 in OD before ordering, and confirm the snap ring groove position matches the shoulder in your bore. Clean the shaft seat, slide the insert on, set the axial position with the snap ring, then tighten both setscrews evenly so the inner ring grips concentrically.

Interchange guidance

The ER envelope is an industry pattern, so ER-20, ER207-20 and SER207-20 inserts from other makers share the 1-1/4 in bore and 2.8346 in OD and generally drop in. Verify seal and flinger arrangement and whether the snap ring is supplied, since those vary between makers even when the envelope matches. A spherical-OD insert of the same bore size — a UC207-20 for example — is a related size, not an interchange: it needs a spherical housing seat.