Electro Hardware S857-MO4-F16-E Circuit Board Spacer No. 4

Product Description

The ELECTRO HARDWARE S857-MO4-F16-E is a round, female unthreaded circuit board spacer designed to maintain consistent standoff clearance between a PCB and its mounting surface. Machined from T-3 grade aluminum to the QQ-A-225A Comp 2 fastener standard, this spacer accepts a No. 4 screw and holds an overall length of 1.25 inches. The bore measures 0.116 inches inside diameter with a tolerance range of 0.000 to 0.010 inches, and the outside diameter is 0.3125 inches. It ships uncoated. Electricians, electronics technicians, and HVAC control board installers use this type of hardware when mounting circuit boards in control enclosures, panels, and equipment chassis.

This spacer is suited for residential and light commercial applications wherever a No. 4 fastener is used to mount a printed circuit board. Typical install scenarios include control board replacement in HVAC equipment, electrical panel subassemblies, and industrial enclosures requiring a precise, fixed standoff height. Its aluminum construction keeps weight low while providing adequate rigidity for stable board mounting. The uncoated finish is appropriate for indoor, non-corrosive environments.

Key Features

• T-3 grade aluminum construction meets QQ-A-225A Comp 2 fastener standard
• Female unthreaded bore accepts No. 4 screws for secure board mounting
• Overall length of 1.25 inches provides consistent standoff height
• Inside diameter of 0.116 inches with a tight tolerance of 0.000 to 0.010 inches
• Outside diameter of 0.3125 inches (5/16 inches) in a round body profile
• Uncoated finish suitable for protected indoor enclosures

Compatibility

Designed as a standard No. 4 screw circuit board spacer for use in any application requiring a female unthreaded round aluminum standoff with a 1.25-inch overall length and 0.3125-inch outside diameter.

Installation Notes

Installation is typically performed by electricians or electronics technicians during control board service or new panel assembly. De-energize the equipment completely before removing or installing any circuit board hardware. Use calibrated hand tools and avoid over-torquing fasteners into the unthreaded bore, as aluminum is softer than steel and threads can strip. Follow applicable NEC guidelines and equipment manufacturer instructions when working inside electrical enclosures.