The 70 mm bore of the MB Series Bearing Lock Washers is the MB14: 70 mm bore, 98 mm outside diameter. This page gives the dimensional row from the table, the shaft and housing fits that suit it, the internal clearance to expect and the mounting, lubrication and failure notes that go with the type.
70 mm Bore Dimensional Row (DIN 5406)
| Designation | For lock nut | Bore d (mm) | Outer diameter D (mm) | Thickness (mm) |
|---|---|---|---|---|
| MB14 | KM14 | 70 | 98 | 1.5 |
What a MB Series Bearing Lock Washers Does
This is a mounting part rather than a bearing: it exists to locate, clamp or seal a bearing. It carries no rating of its own, and the bearing it serves sets the speed, the load and the temperature the assembly can take.
Radial load. Axial load has to be carried by another element in the assembly.
Speed at 70 mm Bore
No limiting speed is tabulated for this product. Where speed matters, the figure to work to is the one the bearing supplier states for the exact design, cage and lubricant supplied — not a family value.
Mounting a 70 mm Bore MB Series Bearing Lock Washers
This bearing is mounted on a tapered adapter sleeve rather than on a machined interference seat. The sleeve is drawn up the shaft by its lock nut and the tapered bore expands the inner ring onto it, so the fit is created by how far the bearing is driven up the taper — measured as a reduction in radial internal clearance or as an axial drive-up distance — and the shaft itself only needs a commercial tolerance. Never judge the fit by feel: a bearing driven too far up the sleeve loses its clearance and runs hot from the first minute.
Lubrication & Relubrication
This part carries no lubricant of its own. The bearing it works with sets the lubrication regime for the assembly.
Failure Modes and What They Look Like
- Subsurface fatigue (spalling) — a flake of raceway lifts out and the bearing gets noisy and rough. This is the failure the L10 life calculation predicts — if it arrives near the calculated life the bearing did its job, and if it arrives early the load, the fit or the lubrication was not what the calculation assumed.
- Inadequate lubrication — a polished, then discoloured, then torn raceway, running hot with a darkened grease. It is the most common cause of early failure by a wide margin, and the interval, not the grease, is usually what was wrong.
- Contamination — dents in the raceway with raised edges, then premature spalling from those dents. Wear particles, casting sand and washdown water all do it; sealing and filtration are what prevent it.
- False brinelling and fretting — evenly spaced dull marks at ball or roller pitch, produced by vibration while the shaft is stationary — a machine that travels on a truck, or a standby pump beside a running one. It is not caused by overload and cannot be cured by fitting a bigger bearing.
Where NOT to Use a MB Series Bearing Lock Washers
- Do not rate this part as though it were the bearing it serves. Its function is to locate, clamp or seal; the bearing next to it sets the load, speed and temperature limits of the assembly.
Stepping Up or Down from 70 mm
Within the same series, the next bore up in this series is 75 mm and the next bore down is 65 mm. Changing bore changes the shaft, so it is the last thing to change: when the calculated life at 70 mm is short, the first move is to a heavier diameter series at the SAME bore — the 6300 envelope instead of the 6200, for instance — which raises the rating without touching the shaft. The second is to change type: a roller bearing carries far more radial load than a ball bearing of the same envelope.
