61868 bearing: complete specifications & equivalents
The 61868 is a ISO 15 radial bearing sized 340 x 420 x 38 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 340 mm |
| Outer diameter D | 420 mm |
| Width B | 38 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN / C3 available |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 178 kN |
| Basic static load rating C0 | 275 kN |
| Fatigue load limit Pu | 6 kN |
| Reference speed (thermal) | 2800 rpm |
| Limiting speed (mechanical) | 1800 rpm |
| Operating temperature | -40 to +150 °C |
| Mass | 10000 g |
| Manufacturer designation | SKF 61868 |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018) |
| Last verified | 2026-09-24 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018)) · extracted 2026-09-24
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018)); SKF® and SKF Explorer® are trademarks of AB SKF, used here for identification only — mpnbase is not an authorized SKF distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at skf.com.
Dimensions in inches & 61800-series range
| Bore d | 13.386 in |
|---|---|
| Outer diameter D | 16.535 in |
| Width B | 1.496 in |
| ISO bore code | 68 |
| Radial section height (D−d)/2 | 40 mm |
| Smallest bore in 61800-series | 1 mm |
| Largest outer diameter in 61800-series | 1820 mm |
| Width range across 61800-series | 1–140 mm |
| Bore position in 61800-series (smallest first) | 49 of 74 |
| Bore above smallest 61800-series size | 339 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 61868 | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier. |
| 61868-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 340×420×38 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
| 61868-MA | SKF | full Dimensions and internal design equivalent — standard interchange. | SKF 61868 MA (machined brass cage, open arrangement) is the same-size execution on the 340×420×38 mm envelope with ratings within 10 % — boundary dimensions interchangeable. |
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 61868 model number is decoded
61868 is supplied open, without shields or seals, so the arrangement around it must supply and retain the lubricant. Within the extra-thin 618xx section (diameter series 8 of ISO 15), multiplying bore code 68 by five gives the 340 mm bore; the 420 mm outside diameter and 38 mm width follow the same boundary-dimension plan. For a rotating inner ring on a 340 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 SKF catalogue this open execution carries the bare designation; protected variants are ordered separately as -2Z and -2RSH.
Typical equipment & failure modes
Common applications
- space-constrained gearboxes
- clutch and transmission assemblies
- robotics and automation joints
- lay shafts and idler shafts
Known failure patterns
- contamination wear from dust and dirt ingress through the open arrangement
- lubricant starvation when no regreasing interval is maintained
- brinelling from static overload or hammering during mounting
- false brinelling from vibration while the shaft is stationary
Selection pitfalls — read before you substitute
- At 340 mm bore the ring mass is significant: heat 61868 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.
- Only 40.0 mm of radial section separates bore and OD on the 618xx series at 340 mm: ring flex from clamping or an oval housing bore transfers straight into raceway stress, so seat roundness matters more here than on a 6268.
- Storage matters for open bearings: 61868 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 61800-series but need a defined regreasing interval; run-to-failure lubrication is the dominant cause of early failure in open 61868 units.
- A 340 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.
- Deep-groove ball bearings tolerate only minutes of misalignment; if the 420 mm housing cannot be aligned, switch to a self-aligning type rather than shimming 61868.
- The open 61868 needs external sealing and application-supplied lubrication; in the SKF catalogue the protected variants are separate order numbers 61868-2Z (shields) and 61868-2RSH (contact seals), not suffix-free 61868.
- The 178/275 kN ratings here are SKF Explorer-class figures from catalogue PUB BU/P1 17000/1 EN (Oct 2018); SKF can revise internal geometry and ratings without changing the designation, so treat the catalogue version and date as part of the specification and re-verify for critical drives.
Frequently asked questions
What are the dimensions of a 61868 bearing?
A 61868 deep-groove ball bearing has a 340 mm bore, 420 mm outer diameter and 38 mm width (13.386 × 16.535 × 1.496 in), per ISO 15 boundary dimensions. It is an open bearing with no seals or shields.
How does the 61868 bore code work?
The last two digits of 61868 are bore code 68, giving 68 × 5 = 340 mm bore. The 420 mm outside diameter and 38 mm width follow the ISO 15 diameter series, not the bore code alone.
What does no suffix on 61868 mean?
A bare 61868 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 61800 compare with other series at the same 340 mm bore?
618 is an extra-thin section: 420×38 mm, only 40.0 mm radial section at 340 mm bore, far smaller than a 6268, for space-limited layouts at the cost of load rating and misalignment tolerance.
What is the SKF designation and catalogue data for 61868?
In the SKF Rolling Bearings catalogue this size is listed as 61868 — the open (unsealed) execution, 340×420×38 mm per ISO 15. Quoted values: C 178 kN, C0 275 kN, Pu 6 kN, limiting speed 1800 r/min, mass 10000 g. Brand suffixes (2Z, 2RSH, 2RSL) differ from the industry-neutral spelling 61868.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018) on 2026-09-24. Read our editorial & correction policy.