61815-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 61815-NSK model number is decoded

In the 61800-series (diameter series 8 of ISO 15) the last two digits encode the bore: 61815 carries bore code 15 = 75 mm. Outside diameter 95 mm and width 10 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 75 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

• Interference on a 75 mm shaft plus running heat consumes radial clearance: where the shaft runs hot or the fit is tight, order 61815 with C3 clearance and re-check the residual value after mounting.
• The 618xx thin section at 75 mm bore has only a 10.0 mm radial section height: it saves space but is highly sensitive to misalignment, shaft deflection and shock loads — verify shaft stiffness before choosing it over a 6215.
• The open 61815-NSK has no lubricant retention: grease escapes and contaminants migrate straight into the 75×95×10 mm raceway, so specify a sealed arrangement for dusty or washdown duty.
• Open bearings tolerate the highest speeds in the 61800-series but need a defined regreasing interval; run-to-failure lubrication is the dominant cause of early failure in open 61815 units.
• Shaft and housing fillets must clear the bearing chamfer so the 10 mm-wide ring seats square; provide an undercut or withdrawal groove instead of relying on an oversized radius.
• A 75 mm bore listing showing the right d/D/B but no standard or precision-class reference may be a loose-tolerance import; measure bore/OD spread before fitting it to a machined shaft.
• The open 61815 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 75 mm bore 61815 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.
• NSK rates 61815 at 13.8 kN dynamic (C) and 13.9 kN static (C0); this light-to-medium rating suits fractional-horsepower drives and instruments — for conveying or gearbox duty with shock loads, verify the equivalent dynamic load stays well below C.
• At 149 g, 61815 is light enough for hand assembly but should be pressed on with a fitting sleeve against the inner ring; do not strike the outer ring or cage with a hammer.
• The 75×95×10 mm envelope of 61815 gives a D/d ratio of 1.27 and only 10.0 mm radial section height — this is an ultra-thin section in NSK's E1103 catalogue 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 13.8/13.9 kN load ratings, mass 149 g here are NSK Rolling Bearings E1103 Part C catalogue figures for 6815 on the 75×95×10 mm ISO 15 envelope; internal geometry and ratings legitimately differ between brands, so re-verify before substituting another manufacturer's 61815 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.
• When replacing a failed unit, inspect the shaft and housing seats before fitting the new 61815 — a new bearing pressed onto a worn or oval seat reproduces the original failure mode in a fraction of its expected life.
• NSK's VV non-contact seal keeps frictional torque close to the open 61815; in motor duty where heat build-up matters, VV is the usual compromise between debris protection and speed capability.