6312-NSK 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 6312-NSK model number is decoded

In the 6300-series (diameter series 3 of ISO 15) the last two digits encode the bore: 6312 carries bore code 12 = 60 mm. Outside diameter 130 mm and width 31 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 60 mm shaft, typical catalogue practice is a k5 shaft seat with an H7 housing bore — verify against the actual load direction and magnitude. 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

• At 60 mm bore, induction heating to roughly 80–100 °C is the clean mounting method; never exceed 120 °C, and hold 6312 against the shaft shoulder while it cools so the ring cannot creep back.
• The 63xx medium series gains rating at 60 mm bore through a 130 mm OD and 31 mm width; the heavier rolling elements also trade away some speed versus a 6212.
• Storage matters for open bearings: 6312-NSK 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.
• 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 6312 units.
• Never mix components between two 6312-NSK units: rings, cage and balls are factory-matched and are not field-interchangeable, even between identical designations.
• The housing bore for the 130 mm OD should be round within IT7; an oval bore pinches the outer ring of 6312-NSK and shows up later as two-point loaded raceway wear.
• The open 6312 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.
• At 60 mm bore 6312 is in NSK's upper general-purpose range; the pressed-steel cage is standard, but mid-section 63xx sizes at this bore can be ordered with a machined brass cage (suffix M) for heavy-shock or very-low-speed duty — confirm cage material with the NSK channel if the application sees impact loads.
• At 90 kN dynamic load rating (C) and 52 kN static (C0), 6312 is a heavy-load NSK bearing for industrial gearboxes and large conveyors; NSK expects a machined brass cage (suffix M) at this rating for shock duty, and the static C0 must be checked against any mounting or lifting loads.
• At 1720 g (1.7 kg), 6312 needs mechanical handling for mounting; NSK recommends induction heating the inner ring (max 120 °C) rather than pressing cold, and a lifting eye if the housing is pre-assembled.
• The 60×130×31 mm envelope of 6312 gives a D/d ratio of 2.17 and 35.0 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 90/52 kN load ratings, mass 1720 g here are NSK Rolling Bearings E1103 Part C catalogue figures for 6312 on the 60×130×31 mm ISO 15 envelope; internal geometry and ratings legitimately differ between brands, so re-verify before substituting another manufacturer's 6312 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.
• NSK supplies its sealed units pre-greased for general duty between roughly -10 and +110 °C; low-temperature, food-grade and high-temperature fills are special executions — ask at order time, because DDU/VV units are not designed to be opened and repacked.
• NSK's VV non-contact seal keeps frictional torque close to the open 6312; in motor duty where heat build-up matters, VV is the usual compromise between debris protection and speed capability.