Lovejoy 69790400050 Rigid Coupling Hub 1.25in Bore Carbon Steel

Product Description

The LOVEJOY 69790400050 is a rigid coupling hub designed for direct-drive power transmission applications. It features a 1.25-inch inside bore and a 3.75-inch outside diameter, machined from carbon steel for strength and durability under load. The hub includes a 0.25-inch wide by 0.125-inch deep keyway, allowing positive rotational engagement with a keyed shaft. This style of coupling hub is used to connect two shafts in a fixed, non-flexible arrangement, and is typically installed by millwrights, mechanical contractors, or maintenance technicians in industrial and commercial equipment applications.

This rigid coupling hub is suited for use in pumps, fans, blowers, compressors, and other rotating equipment where shaft alignment is precise and no flex compensation is needed. The carbon steel construction handles moderate to heavy torque loads. It is sold individually and is appropriate for new installations and direct replacement of worn or damaged hubs in the same bore and OD configuration.

Key Features

• 1.25-inch bore diameter for direct shaft mounting
• 3.75-inch outside diameter for standard hub clearance envelopes
• Keyway slot: 0.25 inches wide by 0.125 inches deep for positive keyed-shaft engagement
• Carbon steel construction for high tensile strength under torsional load
• Rigid design — no flex element, suited for precisely aligned shaft couplings
• Sold as a single hub unit

Compatibility

Designed as an OEM-style replacement or new-installation rigid coupling hub for rotating equipment with a 1.25-inch keyed shaft and a coupling envelope accepting a 3.75-inch OD hub.

Installation Notes

Installation is typically performed by a millwright or qualified mechanical technician. De-energize and lock out the drive motor before any coupling work, following LOTO procedures per OSHA 29 CFR 1910.147. Ensure shaft-to-shaft alignment is within the rigid coupling manufacturer tolerance before final assembly, as rigid hubs provide no misalignment compensation. Use a proper hub puller for removal and a press or installation tool to seat the hub without striking the bore face directly.