618-630-MA bearing: complete specifications & equivalents
The 618-630-MA is a ISO 15 radial bearing sized 630 x 780 x 69 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 630 mm |
| Outer diameter D | 780 mm |
| Width B | 69 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 442 kN |
| Basic static load rating C0 | 965 kN |
| Fatigue load limit Pu | 15.3 kN |
| Reference speed (thermal) | 1400 rpm |
| Limiting speed (mechanical) | 1100 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 73000 g |
| Manufacturer designation | 618/630 MA |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018) |
| Last verified | 2026-09-27 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018)) · extracted 2026-09-27
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 | 24.803 in |
|---|---|
| Outer diameter D | 30.709 in |
| Width B | 2.717 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 75 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) | 61 of 74 |
| Bore above smallest 61800-series size | 629 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the 618-630-MA model number is decoded
In the large-bore 61800-series, the bore is written directly after the slash as 630 mm (large thin-section bores use the slash spelling instead of the two-digit code). The envelope is 630×780×69 mm (24.803×30.709×2.717 in) with a 75.0 mm radial section height, C 442 kN, C0 965 kN and Pu 15.3 kN. The open 618/630 MA carries no shields or seals and relies on application lubrication and external sealing. The MA suffix identifies the machined brass cage execution, a separate order number from the pressed-steel version. Limiting speed 1100 r/min, catalogue mass 73000 g. A thin section saves space but leaves little margin for misalignment or shaft deflection.
Typical equipment & failure modes
Common applications
- robotics and automation joints
- lay shafts and idler shafts
- textile and packaging machinery
- slew and indexing drives
Known failure patterns
- contamination wear when the open arrangement is used without external seals
- lubricant starvation where no regreasing interval is maintained
- fretting corrosion on a creeping shaft or housing seat
- cage damage from running beyond the limiting speed
Selection pitfalls — read before you substitute
- Deep-groove geometry tolerates only minutes of misalignment; if the 780 mm housing bore cannot be aligned, move to a self-aligning bearing rather than shimming 618-630-MA.
- Do not preload 618-630-MA to silence it: a deep-groove ball bearing is not angular-contact, and axial preload only raises temperature and shortens grease life.
- The MA suffix on 618-630-MA denotes a machined brass cage: it is the choice for high speeds, marginal lubrication and shock/vibration duty, and it is temperature-tolerant where polymer cages are not — the 73000 g quoted mass includes the heavier cage.
- Open 618-630-MA needs external sealing at the arrangement level; in dusty housings its life depends entirely on those external seals and the regreasing schedule.
- Plan a relubrication interval for 618-630-MA; run-to-failure on open deep-groove bearings is the dominant early-failure cause.
- Assign interference to the rotating ring: on a conventional shaft-mounted 630 mm position the inner ring rotates, so use a k5/m6 shaft seat with an H7 housing — reverse the logic if the outer ring rotates.
Frequently asked questions
What are the dimensions of 618-630-MA?
The SKF 618/630 MA measures 630 mm bore × 780 mm OD × 69 mm width (24.803 × 30.709 × 2.717 in), mass about 73000 g. It is open, with no shields or seals.
Why is there a slash in the designation 618/630 MA?
The slash writes a bore that falls outside the two-digit code table: 618/630 means 630 mm bore. The site slug 618-630-MA replaces the slash with a hyphen.
What is the difference between 618-630-MA and a same-bore 62-series bearing?
Section height differs: 618-630-MA has a 75 mm radial section and C 442 kN; always match d, D and B — same bore alone never makes two bearings interchangeable.
Which fits should I use for 618-630-MA?
With a rotating inner ring use roughly m6 on the shaft and H7 in the 780 mm housing; reverse the interference if the outer ring rotates.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018) on 2026-09-27. Read our editorial & correction policy.