Boston Gear 08278 Flexible Coupling Half Steel Fc Series

Product Description

The BOSTON GEAR 08278 is a steel flexible coupling half designed for power transmission applications in industrial and mechanical drive systems. Part of the FC Series, this 3-jaw coupling half accepts a bore diameter of 1.876 inches and measures 2.5 inches in outside diameter with an overall length of 4.13 inches. The hub diameter is 2.25 inches with a 1.75 inch bore depth. A 1/4-inch keyway and 3/8-16 thread size are machined in to ensure positive torque transfer and secure shaft engagement. Licensed mechanical technicians and millwrights typically install this component during motor-to-gearbox or pump drive assembly and maintenance work.

The BOSTON GEAR 08278 is suited for use in industrial drive train applications requiring a flexible jaw-style coupling connection. The FC Series designation places it within a standardized family of coupling halves built to consistent bore and OD tolerances. This component is installed as one half of a mating flexible coupling assembly, paired with a corresponding coupling half and an elastomeric spider insert to absorb shock and accommodate minor shaft misalignment. Typical applications include pump drives, compressor drives, and conveyor systems in both light and heavy industrial settings.

Key Features

• Steel construction for durability in industrial drive environments
• 3-jaw style hub for use with standard elastomeric spider inserts
• 1.876 inch bore diameter with 1/4-inch keyway for positive shaft engagement
• 3/8-16 set screw thread for secure shaft clamping
• FC Series coupling size code FC25 for straightforward replacement and cross-reference
• 1.75 inch bore depth accommodates standard shaft end lengths

Compatibility

Designed as an OEM-style replacement coupling half for industrial flexible jaw coupling assemblies within the BOSTON GEAR FC Series, size code FC25. Pair with a matching FC Series coupling half and a compatible elastomeric spider insert to complete the assembly.

Installation Notes

Installation is typically performed by a licensed millwright or mechanical technician. De-energize and lock out all power sources before removing or installing coupling components, following applicable LOTO procedures. Ensure shaft and bore surfaces are clean and free of burrs before seating the coupling half. Do not force the coupling onto the shaft with impact tools, as this may damage bore tolerances or keyway geometry.