How to find the right Shaft-Hub Locking Devices AI guide
Written by an AI model from its trained knowledge.
What the AI looks for in Shaft-Hub Locking Devices
- Shaft diameter and unit system
- The device's inner diameter must equal the shaft's nominal diameter, and inch and metric sizes must never be mixed. Locking devices clamp by friction over a very small radial travel, so even a near-miss size will not grip reliably.
- Rated torque versus required torque
- The catalog transmissible torque must exceed your peak torque multiplied by your application's service factor. Combined torque and axial load must also stay within the combined rating. Exceeding the friction limit causes slip, which galls the shaft and bore and can ruin both.
- Hub outer diameter and wall thickness
- The hub OD must meet the minimum the manufacturer specifies for that device size and your hub material's yield strength. These devices generate high contact pressure, which can crack or permanently expand a thin or soft hub.
- Shaft and bore tolerances and finish
- Machine the shaft and hub bore to the fit and surface roughness in the manufacturer's catalog, commonly about h8 on the shaft and H8 in the bore. Loose fits or rough surfaces reduce contact area and with it the rated torque.
- Device type: internal locking assembly vs shrink disc vs single-nut bushing
- Internal locking assemblies fit between the shaft and the hub bore. Shrink discs clamp the outside of a hollow hub, such as on a shaft-mounted gearbox. Single-nut keyless bushings suit compact, lighter-duty hubs. Each type needs a different hub geometry, so the wrong one simply will not fit the design.
- Self-centering and axial positioning
- Choose a self-centering design when concentricity matters, such as sprockets, pulleys or fast-rotating parts. Choose a design that does not move the hub axially during tightening when its exact position matters. Some designs pull the hub along the shaft or need a separate pilot to keep it running true.
Brands that matter
- Ringfeder: Long-established maker of keyless locking assemblies and shrink discs, with detailed sizing catalogs.
- Fenner Drives (Trantorque, B-LOC): Trantorque single-nut keyless bushings and the B-LOC locking assembly range are common in inch sizes.
- Climax Metal Products: US maker of keyless locking devices and shaft collars, strong on inch sizes.
- Tollok: Italian range of locking assemblies and shrink discs covering many metric sizes.
- KTR (Clampex): KTR's Clampex line offers shaft-hub connections for metric industrial drives.
- Tsubaki (Power-Lock): Power-Lock keyless locking devices for sprocket and pulley mounting.
- BIKON: German specialist in locking assemblies and shrink discs for heavy industrial drives.
- Stüwe: Shrink disc specialist, often specified on hollow-shaft gearboxes.
What to avoid
- Using molybdenum disulfide grease or other friction-reducing compounds on the clamping surfaces, unless the manufacturer specifies it, because it can sharply lower the transmissible torque.
- Tightening the screws in one pass or without a torque wrench; tighten them in stages, crosswise or around the circle, to the catalog tightening torque.
- Mounting on a keyed or damaged shaft section where the keyway or burrs fall under the clamping zone.
- Unbranded devices with no published torque rating, hub OD requirement or tightening torque.
- Reusing a device after it has slipped without inspecting the shaft and bore for galling.
Questions
Can a keyless locking device replace a keyway?
Usually yes, as long as its rated torque covers your peak load with margin. It also avoids the backlash and stress concentration that come with a keyway.
How do I remove a locking assembly that won't release?
Loosen the clamping screws gradually, then use the device's built-in push-off (jacking) threads if it has them. Do not hammer the hub off, because that damages the shaft and the device.