Hillman Fasteners 300039 Split Lock Washer 3/4 in 20PK

Product Description

The HILLMAN FASTENERS 300039 is a split lock washer designed to prevent fastener loosening under vibration and torque load. Made from zinc plated steel, this washer provides corrosion resistance suitable for general mechanical and structural applications. Sold in a 20-pack, it is sized for 3/4 inch fasteners. Plumbers, electricians, HVAC technicians, and general contractors reach for this washer when securing bolts and nuts in installations where vibration or thermal cycling could cause fastener backing. The split design bites into the mating surface and fastener bearing face to maintain clamp load over time.

This split lock washer is suited for residential and light commercial trade applications including equipment mounting, pipe hanger hardware, electrical panel and conduit support, and mechanical room installations. The 3/4 inch size fits standard 3/4 inch bolts commonly used in HVAC equipment bases, pump flanges, and structural support connections. The 20-pack format is practical for single jobs or replenishing a field service kit.

Key Features

• Split lock design creates tension that resists fastener loosening under vibration
• Zinc plated steel construction provides corrosion resistance for general indoor and protected outdoor use
• Sized for 3/4 inch fasteners, a common trade size for equipment mounting hardware
• 20-pack quantity reduces per-unit cost for multi-fastener jobs
• Standard split lock washer profile compatible with common bolt and nut configurations

Compatibility

Designed for use with standard 3/4 inch bolts and nuts in general mechanical, plumbing, electrical, and HVAC fastening applications.

Installation Notes

Split lock washers are installed by placing the washer on the bolt shank between the nut and the mating surface before tightening. Install with the sharp cut edges oriented toward the nut bearing face for maximum bite. Ensure mating surfaces are clean and free of oil or debris before assembly. No specialized trade license is required for fastener installation, but follow applicable mechanical and structural codes for the specific application.