6344 bearing: complete specifications & equivalents
The 6344 is a ISO 15 radial bearing sized 220 x 460 x 88 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NSK |
| Bore diameter d | 220 mm |
| Outer diameter D | 460 mm |
| Width B | 88 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 450 kN |
| Basic static load rating C0 | 520 kN |
| Mass | 73900 g |
| Manufacturer designation | NSK 6344 |
| Standard | ISO 15 |
| Catalog version | NSK Rolling Bearings E1103 Part C |
| Last verified | 2026-09-24 |
Source: catalog reference (NSK Rolling Bearings E1103 Part C) · extracted 2026-09-24
Dimensions in inches & 6300-series range
| Bore d | 8.661 in |
|---|---|
| Outer diameter D | 18.11 in |
| Width B | 3.465 in |
| ISO bore code | 44 |
| Radial section height (D−d)/2 | 120 mm |
| Smallest bore in 6300-series | 10 mm |
| Largest outer diameter in 6300-series | 500 mm |
| Width range across 6300-series | 11–95 mm |
| Bore position in 6300-series (smallest first) | 33 of 34 |
| Bore above smallest 6300-series size | 210 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 6344 | ISO-INTERCHANGE | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension interchange; ratings above are NSK E1103 values and differ by brand — verify per 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 6344 model number is decoded
In the 6300-series (ISO 15 diameter series 3) the last two digits encode the bore: 6344 carries bore code 44 = 220 mm. Outside diameter 460 mm and width 88 mm come from the ISO 15 boundary-dimensions general plan. With no seal suffix the bearing is open: no shields or seals are fitted and lubrication is supplied by the application. For normal-load mounting with a rotating inner ring on a 220 mm shaft, typical catalogue practice is a m6 shaft seat with an H7 housing bore — verify against the actual load direction and magnitude.
Typical equipment & failure modes
Common applications
- medium and heavy industrial drives
- large gearboxes
- industrial fans and blowers
- hoists and winches
Known failure patterns
- contamination wear from dust and dirt ingress through the open arrangement
- lubricant starvation when no regreasing interval is maintained
- raceway smearing under marginal lubrication at start-up
- edge loading from shaft deflection or housing misalignment
Selection pitfalls — read before you substitute
- Mount this 220 mm bore bearing by heating the inner ring (induction heater, max 120 °C) — never drive it home through the outer ring or balls, that brinells the raceways.
- The 63xx medium series gains rating at 220 mm bore through a 460 mm OD and 88 mm width; the heavier rolling elements also trade away some speed versus a 6244.
- The open 6344 has no lubricant retention: grease escapes and contaminants migrate straight into the 220×460×88 mm raceway, so specify a sealed arrangement for dusty or washdown duty.
- Open bearings tolerate the highest speeds in the 6300-series but need a defined regreasing interval; run-to-failure lubrication is the dominant cause of early failure in open 6344 units.
- Suffixes stack in a defined order — clearance follows the seal code, e.g. 6344-C3. No clearance suffix means normal CN clearance.
- The open 6344 needs external sealing and application-supplied lubrication; in the NSK catalogue the protected variants are separate order numbers with suffixes ZZ (shields), VV (non-contact rubber seals) and DDU (contact rubber seals).
- The 450/520 kN ratings, mass 73900 g here are NSK Rolling Bearings E1103 Part C catalogue figures for 6344; this seal/size combination has no counterpart in the SKF 17000 extract used elsewhere on this site, so the page rests on a single manufacturer source — internal geometry and ratings legitimately differ between brands, so re-verify before substituting in a rated drive.
Frequently asked questions
What are the dimensions of a 6344 bearing?
A 6344 deep-groove ball bearing has a 220 mm bore, 460 mm outer diameter and 88 mm width (8.661 × 18.11 × 3.465 in), per ISO 15 boundary dimensions. It is an open bearing with no seals or shields.
How does the 6344 bore code work?
The last two digits of 6344 are bore code 44, giving 44 × 5 = 220 mm bore. The 460 mm outside diameter and 88 mm width follow the ISO 15 diameter series, not the bore code alone.
What does no suffix on 6344 mean?
A bare 6344 designation means open: no shields or seals, normal CN radial clearance and P0 normal tolerance unless further suffixes are ordered. The application must supply and retain the lubrication.
How does the 6300 compare with other series at the same 220 mm bore?
The '3' is the medium diameter series: 460×88 mm, 120.0 mm radial section at 220 mm bore, carrying more load than a 6244 but needing a larger housing bore and giving up some speed.
What is the NSK designation and catalogue data for 6344?
In the NSK Rolling Bearings catalogue (E1103 Part C) this size is listed as 6344 — the open (unsealed) execution, 220×460×88 mm per ISO 15. Quoted values: C 450 kN, C0 520 kN, mass 73900 g. The industry-neutral page spelling 6344 follows the seal-suffix convention used across this site, not NSK order-number spelling. Reference and limiting speeds are not tabulated in the E1103 dimension tables used here; consult NSK speed tables before high-speed service.
Reviewed & verified by the MPN Base engineering desk against source catalog NSK Rolling Bearings E1103 Part C on 2026-09-24. Read our editorial & correction policy.