QJ310 bearing: complete specifications & equivalents
The QJ310 is a ISO 15 radial bearing sized 50 x 110 x 27 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 50 mm |
| Outer diameter D | 110 mm |
| Width B | 27 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 102 kN |
| Basic static load rating C0 | 145 kN |
| Fatigue load limit Pu | 6.2 kN |
| Limiting speed (mechanical) | 5000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 1380 g |
| Manufacturer designation | NTN QJ310 |
| Standard | ISO 15 |
| Catalog version | NTN Ball and Roller Bearings CAT.No.2203E |
| Last verified | 2026-10-01 |
Source: catalog reference (NTN Ball and Roller Bearings CAT.No.2203E) · extracted 2026-10-01
Parameters extracted from the official NTN Ball and Roller Bearings catalogue (NTN Ball and Roller Bearings CAT.No.2203E); NTN® is a trademark of NTN Corporation, used here for identification only — mpnbase is not an authorized NTN distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at ntnglobal.com.
Dimensions in inches & QJ300-series range
| Bore d | 1.969 in |
|---|---|
| Outer diameter D | 4.331 in |
| Width B | 1.063 in |
| ISO bore code | 10 |
| Radial section height (D−d)/2 | 30 mm |
| Smallest bore in QJ300-series | 17 mm |
| Largest outer diameter in QJ300-series | 400 mm |
| Width range across QJ300-series | 14–78 mm |
| Bore position in QJ300-series (smallest first) | 8 of 28 |
| Bore above smallest QJ300-series size | 33 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| QJ310 | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier. |
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 QJ310 model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, QJ310 appears as a heavy-duty QJ300 four-point family bearing of 50 mm bore, 110 mm outside diameter and 27 mm width. Two fields make up the code — QJ3 is the four-point dimension series (heavy-duty QJ300 four-point family) and the last two digits 10 give the bore by the standard code table (50 mm); there is no suffix — the split inner ring and 35 deg contact angle are inherent to the QJ design. The oil rating of 6,700 r/min sits 1,700 r/min above the 5,000 r/min grease figure — a 1.34x step that says how much headroom oil cooling buys. The 50/110/27 envelope is an ISO 15 boundary plan, so dimensional interchange with other makers holds — ratings and internal geometry do not automatically follow. Shaft and housing shoulders must clear the ring corners yet support enough face — the catalogue abutment diameters for the 50 mm bore give the working limits.
Typical equipment & failure modes
Common applications
- gearbox input shafts under helical-gear thrust
- electric motor shafts with axial locating duty
- conveyor drive and tension-drum shafts
- agricultural gearbox and PTO shaft supports
Known failure patterns
- impact brinelling dents on the 30 deg contact path after a shaft-side hammer blow during mounting, because axial shock travels straight through the contact angle
- thermal runaway from excessive preload: the pair runs hot, grease darkens and the contact ellipse spreads until the raceways smear
- pressed-steel cage pocket wear and rivet loosening after repeated ball skid at light load and high speed
- contamination-induced denting — hard particles rolled into the contact ellipse become the initiation points for surface fatigue
- contamination-induced denting — hard particles rolled into the contact ellipse become the initiation points for surface fatigue
Selection pitfalls — read before you substitute
- In this size class the common miss is lubrication interval, not fit — a 50 mm spindle at the catalogue speeds needs a calculated relubrication plan, not a calendar one.
- The QJ split inner ring must be clamped by the shaft nut/shoulder on both halves — assembling it against a single small shoulder leaves one half-ring free to walk.
- Never use a four-point or double-row bearing as a like-for-like swap for a single QJ310 without re-checking axial float, heat and housing width — the kinematics differ.
- A single-row angular contact left loose on the shaft to "help assembly" will fret the seat: the contact angle keeps driving the ring axially under load.
- Grease rated for deep-groove motor duty is not automatically right at 5,000 r/min with preload; check the grease speed factor against the catalogue figure.
- The 102/145 kN ratings and 6.2 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for QJ310; internal geometry legitimately differs between manufacturers, so re-verify ratings, contact angle and suffix before substituting another make on a rated drive.
Frequently asked questions
What are the dimensions and catalogue ratings of NTN QJ310?
QJ310 is a four-point contact ball bearing to ISO 15: 50 mm bore, 110 mm outside diameter, 27 mm width (1.969 x 4.331 x 1.063 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 102 kN, C0 145 kN and a 6.2 kN fatigue load limit Pu; the grease limiting speed is 5,000 r/min and the oil rating 6,700 r/min; mass about 1380 g.
How is the QJ310 designation structured?
QJ3 is the four-point dimension series (heavy-duty QJ300 four-point family); the last two digits 10 give the bore by the standard code table (50 mm); there is no suffix — the split inner ring and 35 deg contact angle are inherent to the QJ design. The 110 mm OD and 27 mm width follow the ISO 15 boundary-dimension plan for that series.
Which axial direction does QJ310 support?
QJ310 is a four-point contact bearing: the split inner ring lets each ball touch the raceways at two points, so one bearing locates the shaft in both axial directions at its 35 deg contact angle. It is normally mounted with slight radial clearance against the housing as the axial-locating member.
What lubrication speeds does NTN print for QJ310?
Per NTN Ball and Roller Bearings CAT.No.2203E, the grease limiting speed is 5,000 r/min and the oil rating 6,700 r/min. These are catalogue ceilings for a correctly mounted bearing with the stated lubricant; preload, fill quantity, ambient heat and paired arrangements all move the real limit.
What should be checked before substituting another make for QJ310?
The 50/110/27 mm envelope is ISO 15 interchangeable, but internal geometry — contact angle, osculation, cage and shoulder details — is maker-specific. Re-verify C 102 kN / C0 145 kN, the speed figures, contact angle and suffix meaning against the donor catalogue before swapping on a rated drive.
Reviewed & verified by the MPN Base engineering desk against source catalog NTN Ball and Roller Bearings CAT.No.2203E on 2026-10-01. Read our editorial & correction policy.