QJ314 bearing: complete specifications & equivalents
The QJ314 is a ISO 15 radial bearing sized 70 x 150 x 35 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 70 mm |
| Outer diameter D | 150 mm |
| Width B | 35 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 172 kN |
| Basic static load rating C0 | 260 kN |
| Fatigue load limit Pu | 10.7 kN |
| Limiting speed (mechanical) | 3600 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 3270 g |
| Manufacturer designation | NTN QJ314 |
| 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 | 2.756 in |
|---|---|
| Outer diameter D | 5.906 in |
| Width B | 1.378 in |
| ISO bore code | 14 |
| Radial section height (D−d)/2 | 40 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) | 12 of 28 |
| Bore above smallest QJ300-series size | 53 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| QJ314 | 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 QJ314 model number is decoded
QJ314 is the 70 mm bore member of NTN's heavy-duty QJ300 four-point family, with a 150 mm outside diameter and 35 mm section width. Reading the code: QJ3 is the four-point dimension series (heavy-duty QJ300 four-point family), the last two digits 14 give the bore by the standard code table (70 mm); there is no suffix — the split inner ring and 35 deg contact angle are inherent to the QJ design. Because the contact line is angled, one bearing of this type takes radial load plus thrust from one direction only — the opposite direction needs a second bearing or a matched set. Size selection is usually finished by checking that the C0 of 260 kN covers the maximum static or shock condition with the catalogue safety factor, not only the running load. Set preload or end-play with the pair as a unit and lock the adjustment; a single angular-contact bearing cannot run free like a deep-groove one.
Typical equipment & failure modes
Common applications
- paper-machine roll and calendar drives
- extruder and mixer gearbox output shafts
- mining conveyor head-shaft positions
- marine auxiliary and winch gearbox shafts
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
- resin-cage cracking on the 7900-series sizes after hot, dry running or solvent attack on the polymer
- flaking that starts at the raceway shoulder on the thrust-loaded side when axial load repeatedly exceeds the design share
- edge loading and early spalling from housing bores that are out of round or shoulders that are too small for the ring face
Selection pitfalls — read before you substitute
- Bearings of 70 mm bore arrive heavy enough that handling damage (dents from slings, tilting on the shaft) is a real failure precursor — use proper lifting and heating kit.
- 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.
- Substituting the B (40 deg) execution for the standard 30 deg bearing changes the axial/radial load split — the shaft position and the mating bearing see different forces even though the envelope is identical.
- If the application vibrates at standstill (transport, idle machine next to a running line), specify protection: the contact ellipse of a preloaded bearing false-brinells faster than a loose one.
- The 3,600 r/min speed figure assumes the catalogue lubrication state and a correctly set pair; real limits drop fast with excess grease fill or heavy preload.
- The 172/260 kN ratings and 10.7 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for QJ314; 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 QJ314?
QJ314 is a four-point contact ball bearing to ISO 15: 70 mm bore, 150 mm outside diameter, 35 mm width (2.756 x 5.906 x 1.378 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 172 kN, C0 260 kN and a 10.7 kN fatigue load limit Pu; the grease limiting speed is 3,600 r/min and the oil rating 4,800 r/min; mass about 3270 g.
How is the QJ314 designation structured?
QJ3 is the four-point dimension series (heavy-duty QJ300 four-point family); the last two digits 14 give the bore by the standard code table (70 mm); there is no suffix — the split inner ring and 35 deg contact angle are inherent to the QJ design. The 150 mm OD and 35 mm width follow the ISO 15 boundary-dimension plan for that series.
Which axial direction does QJ314 support?
QJ314 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 QJ314?
Per NTN Ball and Roller Bearings CAT.No.2203E, the grease limiting speed is 3,600 r/min and the oil rating 4,800 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 QJ314?
The 70/150/35 mm envelope is ISO 15 interchangeable, but internal geometry — contact angle, osculation, cage and shoulder details — is maker-specific. Re-verify C 172 kN / C0 260 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.