61964 bearing: complete specifications & equivalents
The 61964 is a ISO 15 radial bearing sized 320 x 440 x 56 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 320 mm |
| Outer diameter D | 440 mm |
| Width B | 56 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 315 kN |
| Basic static load rating C0 | 405 kN |
| Fatigue load limit Pu | 14.1 kN |
| Limiting speed (mechanical) | 1300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 24800 g |
| Manufacturer designation | 6964 |
| Standard | ISO 15 |
| Catalog version | NTN Ball and Roller Bearings CAT.No.2203-3/E (2024) |
| Last verified | 2026-09-25 |
Source: catalog reference (NTN Ball and Roller Bearings CAT.No.2203-3/E (2024)) · extracted 2026-09-25
Parameters extracted from the official NTN Ball and Roller Bearings catalogue (NTN Ball and Roller Bearings CAT.No.2203-3/E (2024)); 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 & 61900-series range
| Bore d | 12.598 in |
|---|---|
| Outer diameter D | 17.323 in |
| Width B | 2.205 in |
| ISO bore code | 64 |
| Radial section height (D−d)/2 | 60 mm |
| Smallest bore in 61900-series | 3 mm |
| Largest outer diameter in 61900-series | 1120 mm |
| Width range across 61900-series | 3–118 mm |
| Bore position in 61900-series (smallest first) | 45 of 63 |
| Bore above smallest 61900-series size | 317 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 61964-MA | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 320×440×56 mm envelope per ISO 15; seal variant and load ratings may differ — confirm sealing and rating before substituting. |
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 61964 model number is decoded
61964 is supplied open, without shields or seals, so the arrangement around it must supply and retain the lubricant. Within the thin 619xx section (diameter series 9 of ISO 15), multiplying bore code 64 by five gives the 320 mm bore; the 440 mm outside diameter and 56 mm width follow the same boundary-dimension plan. For a rotating inner ring on a 320 mm shaft under normal load, catalogue practice seats it on a m6 shaft fit with an H7 housing bore — confirm against the actual load direction and magnitude before committing. In the NTN catalogue this open execution carries the bare designation; protected variants are ordered separately with suffixes ZZ (shields), LLB/LLF (non-contact seals), LLH (low-torque contact seal) and LLU (contact seal).
Typical equipment & failure modes
Common applications
- robotics and automation joints
- lay shafts and idler shafts
- textile machinery
- packaging machinery
Known failure patterns
- contamination wear from dust and dirt ingress through the open arrangement
- lubricant starvation when no regreasing interval is maintained
- edge loading from shaft deflection or housing misalignment
- rolling-contact fatigue spalling after the rated L10 life is exceeded
Selection pitfalls — read before you substitute
- At 320 mm bore the ring mass is significant: heat 61964 on an induction heater (max 120 °C), never over an open flame, and plan puller access or a withdrawal sleeve now for the day it has to come off again.
- The 619xx thin section at 320 mm bore (60.0 mm section height) cannot shrug off the misalignment a standard section tolerates; keep the housing bores round and aligned, or edge contact will spall the raceways early.
- The open 61964 has no lubricant retention: grease escapes and contaminants migrate straight into the 320×440×56 mm raceway, so specify a sealed arrangement for dusty or washdown duty.
- Open bearings tolerate the highest speeds in the 61900-series but need a defined regreasing interval; run-to-failure lubrication is the dominant cause of early failure in open 61964 units.
- Deep-groove ball bearings tolerate only minutes of misalignment; if the 440 mm housing cannot be aligned, switch to a self-aligning type rather than shimming 61964.
- Do not quieten a noisy bearing by preloading it: the 61900-series is a deep-groove design, not angular-contact; axial preload raises temperature and shortens grease life.
- The open 61964 has no integral sealing; in the NTN 2203 catalogue the protected variants carry suffixes ZZ (non-contact steel shields), LLB/LLF (non-contact rubber seals), LLU (contact rubber seals) and LLH (a low-torque contact seal with higher speed capability than LLU). A JR or JRX suffix (printed for some thin-section sizes) denotes a pressed-steel cage, not a seal.
- The 320 mm bore places 61964 in NTN's extra-large range; the pressed-steel cage is not recommended at this diameter and NTN supplies a machined brass cage (suffix M) as the standard offering. Speed ratings are low, housing alignment is critical, and oil lubrication with a defined relubrication interval is mandatory — consult NTN engineering before sizing.
- NTN lists the grease limiting speed at 1300 r/min for 61964; this is a large-section size where the pressed-steel cage is speed-limited — NTN recommends the machined brass cage (suffix M) and oil lubrication for any continuous operation above this figure.
- NTN rates 61964 at 315 kN dynamic (C) and 405 kN static (C0), 14.1 kN fatigue load limit Cu; this is an upper heavy-load rating where the pressed-steel cage is not recommended — NTN supplies a machined brass cage (suffix M) and the static C0 must be verified against any shock or lifting loads the bearing sees during mounting.
- At 24800 g (24.8 kg), 61964 is a very heavy bearing where handling and mounting method directly affect service life; NTN requires induction heating of the inner ring (max 120 °C), a mechanical puller for removal, and a defined lifting procedure to avoid damaging the machined brass cage.
- The 320×440×56 mm envelope of 61964 gives a D/d ratio of 1.38 and only 60.0 mm radial section height — this is an ultra-thin section where shaft deflection and housing ovality directly load the ball-raceway contact; verify shaft stiffness (target deflection under 0.05 mm) before specifying it over a 62-series.
- The 315/405 kN load ratings, 14.1 kN fatigue load limit Cu NTN lists the grease limiting speed at 1300 r/min for this designation; oil-mist or jet lubrication raises the ceiling but requires a sealed-housing review. and 24800 g mass here are NTN Ball and Roller Bearings CAT.No.2203-3/E figures for 6964 on the 320×440×56 mm ISO 15 envelope; internal geometry and ratings legitimately differ between brands, so re-verify before substituting another manufacturer's 61964 in a rated drive.
- Two NTN bearings of the same designation from different production lots can carry minor internal-geometry revisions; for paired or preloaded arrangements on one shaft, order a single lot through the NTN distributor.
- Order the C3 internal-clearance version (61964 with C3 after the seal code) when the shaft fit is tight or the shaft-to-housing temperature gradient exceeds roughly 10 °C — the residual clearance after mounting, not the catalogue CN figure, decides service life.
Frequently asked questions
What are the dimensions of a 61964 bearing?
A 61964 deep-groove ball bearing has a 320 mm bore, 440 mm outer diameter and 56 mm width (12.598 × 17.323 × 2.205 in), per ISO 15 boundary dimensions. It is an open bearing with no seals or shields.
How should 61964 be mounted?
Apply the mounting force to the ring being fitted: on a 320 mm shaft seat the press load must pass through the inner-ring face only. Induction heating of the inner ring (max 120 °C) is the clean method at this size. Never strike the outer ring, the cage or the seals.
What lubrication does 61964 need?
The open 61964 is lubricated by the application; a NLGI 2 lithium-soap grease filled to roughly 25–35% of the free volume is the common choice, with a defined relubrication interval.
What is the NTN order number for an open 61964?
NTN lists the open 61964 under the bare designation 6964; protected versions use suffixes ZZ (shields), LLB/LLF (non-contact seals), LLH (low-torque contact seal) and LLU (contact seal) on the same 320 mm bore envelope.
What cage does NTN fit in 6964?
Standard is a pressed-steel cage with no suffix; larger sizes or shock-loaded duty can be supplied with a machined brass cage (suffix M) as a separate order number. The catalogue figures quoted here are for the pressed-steel execution.
Reviewed & verified by the MPN Base engineering desk against source catalog NTN Ball and Roller Bearings CAT.No.2203-3/E (2024) on 2026-09-25. Read our editorial & correction policy.