240-630BK30 bearing: complete specifications & equivalents
The 240-630BK30 is a ISO 15 radial bearing sized 630 x 920 x 290 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 630 mm |
| Outer diameter D | 920 mm |
| Width B | 290 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 8400 kN |
| Basic static load rating C0 | 17900 kN |
| Fatigue load limit Pu | 915 kN |
| Limiting speed (mechanical) | 270 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 646000 g |
| Manufacturer designation | NTN 240/630BK30 |
| 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 & 24000-series range
| Bore d | 24.803 in |
|---|---|
| Outer diameter D | 36.22 in |
| Width B | 11.417 in |
| ISO bore code | 40 |
| Radial section height (D−d)/2 | 145 mm |
| Smallest bore in 24000-series | 65 mm |
| Largest outer diameter in 24000-series | 1580 mm |
| Width range across 24000-series | 35–462 mm |
| Bore position in 24000-series (smallest first) | 32 of 42 |
| Bore above smallest 24000-series size | 565 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 240-630B | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same NTN 24000-series envelope, cage and ratings; this is the tapered-bore execution (K30, 1:30) of the cylindrical-bore 240-630B — mounting (adapter/withdrawal sleeve or tapered seat, drive-up) differs. Verify shaft arrangement. |
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 240-630BK30 model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, 240/630BK30 denotes the 630 mm bore spherical roller bearing (8400 kN C / 17900 kN C0) in the 24000 series, the self-aligning choice for heavy combined load. Reading the full code: the number gives the 630×920 mm envelope, — names the cage/capacity execution, K30 marks the 1:30 tapered bore for sleeve mounting, and plain outer ring (no D1/W33 groove) completes the order number. NTN prints two speeds for 240/630BK30: 270 r/min grease and 350 r/min oil — the gap of 80 r/min reflects oil cooling of the heavy roller set. Selection: the C0/C ratio of 2.13 (17900/8400 kN) reflects the heavy static and shock proportioning of 240/630BK30; size the equivalent load at the required L10 with shock factor for the application. Mount 240/630BK30 on its adapter or withdrawal sleeve on the 630 mm plain shaft: oil the sleeve, fit the lock nut, drive up to the NTN-specified residual clearance (or use oil injection on large seats), then lock the tab washer.
Typical equipment & failure modes
Common applications
- steel-mill and heavy crusher main shafts
- mining shovel and dragline swing shafts
- cement-rotary-kiln support and trunnion rolls
- large SAG/ball-mill trunnion and pinion shafts
Known failure patterns
- lubricant starvation at the centre rib area when the D1/W33 groove is not connected to a relubrication supply
- pressed EA cage fatigue under sustained vibration when minimum load is not maintained
- micro-pitting when the EHL film is thinner than the raceway composite roughness
- water-induced pitting in washdown or outdoor duty without effective external seals
- asymmetric wear on the two roller rows from sustained angular misalignment beyond the self-aligning range
Selection pitfalls — read before you substitute
- At 630 mm bore 240/630BK30 is normally mounted on adapter/withdrawal sleeves with hydraulic assistance; follow the NTN drive-up angle or oil-injection procedure — manual nut tightening cannot set the multi-tonne seating correctly.
- Self-aligning does not mean unlimited misalignment: beyond the catalogue angle the outer ring's spherical travel is exhausted and the 8400 kN rating no longer applies.
- The 1:30 tapered bore is the only difference from the cylindrical-bore 240/630B: envelopes and ratings match, but drive-up tooling, sleeve and seat do not — never mix the two mounting methods.
- The two roller rows must share load equally — a tilted spacer or unequal abutment on the 290 mm-wide ring loads one row only and shows as asymmetric race polish during inspection.
- Oil relubrication toward 350 r/min needs drain and level design; flooding the 290 mm cavity churns heat through the heavy roller set and cage despite the higher oil speed figure.
- The 8400/17900 kN ratings, 915 kN Pu and 646000 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for 240/630BK30 (basic); another maker's same-envelope part revises internal geometry, so re-verify ratings and cage before substitution on vibrating or rated drives.
Frequently asked questions
What are the dimensions and catalogue data of 240/630BK30?
240/630BK30 is an NTN double-row spherical roller bearing to ISO 15: 630 mm bore, 920 mm OD and 290 mm width (24.803 × 36.22 × 11.417 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 8400 kN, C0 17900 kN, Pu 915 kN, grease limiting speed 270 r/min, oil 350 r/min, mass about 646000 g. It is open, with pressed-steel cage (standard execution) and a 1:30 tapered bore.
What is the difference between the K/K30 tapered bore and the cylindrical bore versions?
K30 denotes a 1:30 tapered bore (the wide 24000 series). 240/630BK30 mounts on a matching adapter or withdrawal sleeve on a plain 630 mm shaft and is driven up to a measured radial clearance; the cylindrical-bore counterpart is 240/630B.
What do EA and EM mean on NTN spherical roller bearings?
EA is the NTN standard-capacity/high-capacity execution with a pressed sheet-steel window cage; EM is the high-capacity execution with a one-piece machined brass cage. Both use the optimised symmetric-roller design, but cage identity changes mass, speed behaviour and suitability for duties like vibrating screens, so they are separate order numbers. 240/630BK30 is the basic execution.
What do D1 and W33 mean on 240/630BK30?
240/630BK30 is listed without a D1/W33 outer-ring groove in 2203E; lubrication is supplied from the ring sides. D1 (NTN spelling) and W33 add the annular groove plus holes and are ordered as distinct suffixed executions of the same envelope.
How much misalignment and axial load can 240/630BK30 take?
The sphered outer raceway compensates static and dynamic misalignment in the order of 1–2° (verify the exact 2203E figure for the 24000 series); beyond that, load concentrates on one roller row. Load is predominantly radial with a moderate axial share in either direction — 8400 kN C / 17900 kN C0 — but sustained pure axial load is not recommended because it unloads one row.
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.