6348 bearing: complete specifications & equivalents

Specification table

Source: catalog reference (NSK Rolling Bearings E1103 Part C) · extracted 2026-09-24

Cross references & equivalents

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 6348 model number is decoded

6348 is supplied open, without shields or seals, so the arrangement around it must supply and retain the lubricant. Within the medium 63xx section (diameter series 3 of ISO 15), multiplying bore code 48 by five gives the 240 mm bore; the 500 mm outside diameter and 95 mm width follow the same boundary-dimension plan. For a rotating inner ring on a 240 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 NSK catalogue this open execution carries the bare designation; protected variants are ordered separately with suffixes ZZ (steel shields), VV (non-contact rubber seals) and DDU (contact rubber seals).

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Large bores like the 240 mm of 6348 demand clean, burr-free seats; one raised burr under a ring this size cocks the bearing and concentrates load at the raceway edge, cutting life drastically.
• The 63xx medium series gains rating at 240 mm bore through a 500 mm OD and 95 mm width; the heavier rolling elements also trade away some speed versus a 6248.
• The open 6348 has no lubricant retention: grease escapes and contaminants migrate straight into the 240×500×95 mm raceway, so specify a sealed arrangement for dusty or washdown duty.
• Storage matters for open bearings: 6348 leaves the factory with rust preventive only, so clean it and apply the service grease at assembly even if the rings look oily from the wrapper.
• Never mix components between two 6348 units: rings, cage and balls are factory-matched and are not field-interchangeable, even between identical designations.
• Axial location must clamp the ring face, not the seal area: a shoulder or circlip bearing on the seal side of the 95 mm-wide ring of 6348 drags the lip and overheats it.
• The open 6348 has no integral sealing; in the NSK E1103 catalogue the protected variants carry suffixes ZZ (non-contact steel shields), VV (non-contact rubber seals) and DDU (contact rubber seals). NSK does not offer a low-torque contact seal equivalent to NTN's LLH in this catalogue — for high-speed sealed duty specify the VV non-contact seal and an external housing labyrinth.
• The 240 mm bore places 6348 at the upper end of NSK's single-row deep-groove catalogue for the E1103 Part C extract; this is a heavy-engineering bearing where centrifugal force and cage inertia dominate the design envelope. NSK supplies a machined brass cage (suffix M) and expects oil lubrication with a defined relubrication interval — do not use catalogue grease speed figures for this size without an NSK engineering review.
• NSK rates 6348 at 515 kN dynamic (C) and 625 kN static (C0); this is an extreme-load bearing at the top of the E1103 Part C single-row deep-groove range, where mounting, shaft stiffness and housing alignment dominate the achievable life. Consult NSK engineering for a full application review rather than relying on catalogue L10 alone.
• At 94400 g (94.4 kg), 6348 is a very heavy NSK bearing where handling and mounting method directly affect service life; NSK requires induction heating of the inner ring (max 120 °C), a mechanical puller for removal, and a defined lifting procedure to avoid damaging the cage.
• The 240×500×95 mm envelope of 6348 gives a D/d ratio of 2.08 and 130.0 mm radial section height — a heavy NSK section built for high-load, lower-speed duty; specifying it in a high-rpm motor generates excess heat and shortens grease life, so prefer a 62/63-series there.
• The 515/625 kN load ratings, mass 94400 g here are NSK Rolling Bearings E1103 Part C catalogue figures for 6348 on the 240×500×95 mm ISO 15 envelope; internal geometry and ratings legitimately differ between brands, so re-verify before substituting another manufacturer's 6348 in a rated drive. NSK does not tabulate reference or limiting speeds in the E1103 Part C dimension tables used for this page — consult NSK's separate speed-rating tables before high-speed service.
• Standard P0 runout from NSK is adequate up to the catalogue limiting speed on ground shaft seats; spindle or instrument positions should specify P6/P5 accuracy explicitly — it is a different order code, not a sorting of standard stock.
• When replacing a failed unit, inspect the shaft and housing seats before fitting the new 6348 — a new bearing pressed onto a worn or oval seat reproduces the original failure mode in a fraction of its expected life.