QJ-307-N2PHAS 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-307-N2PHAS model number is decoded

QJ 307 N2PHAS is SKF's 35 mm-bore QJ four-point contact ball bearing of the QJ300 series, 35×80×21 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. N2 marks two locating slots, 180° apart, in one outer-ring side face: pins or dogs engage the slots to stop the outer ring turning in its radially-clear housing bore. 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 35×80×21 mm (1.378×3.15×0.827 in), 22.5 mm radial section height, C 64 kN, C0 51 kN, Pu 2.16 kN.SKF publishes only the 15,000 r/min limiting speed for this execution, catalogue mass 570 g. Load balance: C0 51 kN against C 64 kN gives a 0.80 ratio, typical of a four-point thrust-oriented design; Pu 2.16 kN enters the SKF adjusted-life equation rather than the basic rating life. Mass and section check: 570 g inside the 35×80×21 mm outline leaves a 22.5 mm radial section, and the 51 kN static rating is 0.80× the dynamic rating — plan static safety and minimum load against those numbers rather than against sister executions. Bore-to-OD planning: OD 80 over bore 35 is a 2.29× step for this size, and the 21 mm width gives a bore/width ratio of 1.67; use these ratios when housing space around the 35 mm shaft is the first constraint. Locating-slot execution: the two N2 notches are milled into one outer-ring side face exactly 180 degrees apart and engaged by housing dogs or headed pins during assembly; verify dog engagement by hand before the cover goes on, deburr the slot edges after any housing rework, and re-inspect the slot roots for fretting marks at each overhaul because a dog that rides only one slot lets the outer ring walk. The slots identify this order number unmistakably: the plain MA/PHAS execution of the same bore has no notches and must be secured differently.

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.
• Provide a minimum axial load (spring preload is common) so the balls stay correctly seated at speed and light-load conditions; otherwise they skid.
• 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 built into QJ-307-N2PHAS: check the two N2 slot faces and the engaging housing dogs at every refit, and never rely on cover friction to stop the radially loose outer ring.
• The PHAS PEEK cage of QJ-307-N2PHAS 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 307 N2PHAS as the qj slotted execution; the other order numbers of the QJ 307 size are different products and may carry different ratings — always quote the full designation when purchasing.