QJ307 bearing: complete specifications & equivalents
The QJ307 is a ISO 15 radial bearing sized 35 x 80 x 21 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 35 mm |
| Outer diameter D | 80 mm |
| Width B | 21 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 55 kN |
| Basic static load rating C0 | 73 kN |
| Fatigue load limit Pu | 3.15 kN |
| Limiting speed (mechanical) | 7000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 570 g |
| Manufacturer designation | NTN QJ307 |
| 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 | 1.378 in |
|---|---|
| Outer diameter D | 3.15 in |
| Width B | 0.827 in |
| ISO bore code | 07 |
| Radial section height (D−d)/2 | 22.5 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) | 5 of 28 |
| Bore above smallest QJ300-series size | 18 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| QJ307 | 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 QJ307 model number is decoded
QJ307 is the 35 mm bore member of NTN's heavy-duty QJ300 four-point family, with a 80 mm outside diameter and 21 mm section 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 07 give the bore by the standard code table (35 mm); there is no suffix — the split inner ring and 35 deg contact angle are inherent to the QJ design. Catalogue mass is about 570 g, which at this 22.5 mm radial section keeps the bearing comfortably inside high-speed spindle weight budgets. Choose the heavy-duty QJ300 four-point family when the shaft needs a stiff locating support and the axial component is known to act mostly one way. Heat-mounting to 80-90 deg C is the clean route onto a 35 mm shaft; drive-fits through the balls transmit force through the contact ellipse and can brinell it.
Typical equipment & failure modes
Common applications
- industrial pump and blower impeller shafts
- gearbox input shafts under helical-gear thrust
- electric motor shafts with axial locating duty
- conveyor drive and tension-drum 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
- pressed-steel cage pocket wear and rivet loosening after repeated ball skid at light load and high speed
- edge loading and early spalling from housing bores that are out of round or shoulders that are too small for the ring face
- 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 35 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.
- A QJ307 mounted the wrong way round still turns smoothly by hand; the failure shows up weeks later as raceway flaking on the unloaded-looking side.
- The 7,000 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.
- 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 55/73 kN ratings and 3.15 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for QJ307; 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 QJ307?
QJ307 is a four-point contact ball bearing to ISO 15: 35 mm bore, 80 mm outside diameter, 21 mm width (1.378 x 3.15 x 0.827 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 55 kN, C0 73 kN and a 3.15 kN fatigue load limit Pu; the grease limiting speed is 7,000 r/min and the oil rating 9,300 r/min; mass about 570 g.
How is the QJ307 designation structured?
QJ3 is the four-point dimension series (heavy-duty QJ300 four-point family); the last two digits 07 give the bore by the standard code table (35 mm); there is no suffix — the split inner ring and 35 deg contact angle are inherent to the QJ design. The 80 mm OD and 21 mm width follow the ISO 15 boundary-dimension plan for that series.
Which axial direction does QJ307 support?
QJ307 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 QJ307?
Per NTN Ball and Roller Bearings CAT.No.2203E, the grease limiting speed is 7,000 r/min and the oil rating 9,300 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 QJ307?
The 35/80/21 mm envelope is ISO 15 interchangeable, but internal geometry — contact angle, osculation, cage and shoulder details — is maker-specific. Re-verify C 55 kN / C0 73 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.