QJ-309-PHAS bearing: complete specifications & equivalents

Specification table

Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018)) · extracted 2026-09-27

Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018)); SKF® and SKF Explorer® are trademarks of AB SKF, used here for identification only — mpnbase is not an authorized SKF distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at skf.com.

Cross references & equivalents

Interchange levels: full standard interchange · partial verify parameters · verify manual confirmation required. Links resolve to the equivalent model's specification page where available.

How the QJ-309-PHAS model number is decoded

QJ 309 PHAS is SKF's 45 mm-bore QJ four-point contact ball bearing of the QJ300 series, 45×100×25 mm, with a two-piece inner ring for bidirectional axial location beside a radial bearing. QJ identifies a four-point contact ball bearing with a two-piece inner ring: the gothic-arch raceways seat each ball at four points, giving axial location in both directions while a paired radial bearing carries the radial load. glass-fibre reinforced PEEK cage, outer-ring-centred with lubrication grooves in the guiding surfaces (suffix PHAS), for very high-speed oil-air or grease lubrication. Envelope 45×100×25 mm (1.772×3.937×0.984 in), 27.5 mm radial section height, C 100 kN, C0 83 kN, Pu 3.55 kN.SKF publishes only the 12,000 r/min limiting speed for this execution, catalogue mass 1050 g. Envelope economics: the 25 mm width over a 27.5 mm section yields 0.91 mm of ring width per section millimetre, and the bearing weighs 1050 g for 100 kN of dynamic capacity — about 11 g per rated kN. Selection figures for QJ 309 PHAS: the static-to-dynamic ratio C0/C is 0.83, Pu 3.55 kN is about 4 % of C, and catalogue mass works out to roughly 23 g per millimetre of bore. Bore-to-OD planning: OD 100 over bore 45 is a 2.22× step for this size, and the 25 mm width gives a bore/width ratio of 1.80; use these ratios when housing space around the 45 mm shaft is the first constraint. Plain outer-ring execution: this order number is delivered without N2 locating slots, so anti-rotation is solved in the housing instead — a shoulder dog, a spring-loaded key, a cover feature or an interference-free circlip arrangement. Because the outer ring deliberately runs with radial clearance and a small axial float gap, omitting positive anti-rotation invites seat fretting; the slotted N2 order number is the alternative when the housing can provide engagement pins.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Keep a small axial gap between the outer ring and the cover flange so it can accommodate thermal movement; never clamp the outer ring solid.
• Keep a small axial gap between the outer ring and the cover flange so it can accommodate thermal movement; never clamp the outer ring solid.
• Keep a small axial gap between the outer ring and the cover flange so it can accommodate thermal movement; never clamp the outer ring solid.
• Anti-rotation is NOT built into QJ-309-PHAS: without N2 slots the housing must provide a dog, keyed cover or other positive stop, since the outer ring runs radially loose by design.
• The PHAS PEEK cage of QJ-309-PHAS is outer-ring-centred with lubrication grooves: feed clean oil-air or appropriate grease to the guide land and inspect groove filling at overhaul.
• Catalogue ratings are SKF PUB BU/P1 17000 figures for QJ 309 PHAS as the qj plain execution; the other order numbers of the QJ 309 size are different products and may carry different ratings — always quote the full designation when purchasing.