Klein Tools 640-5/16 Hollow Shaft Nut Driver 5/16 in

Product Description

The KLEIN TOOLS 640-5/16 is a hollow shaft nut driver designed for fastening and loosening hex nuts in HVAC, electrical, and general trade applications. The hollow shaft design allows the driver to seat fully over long threaded studs and bolt shafts that extend beyond the nut face, making it a practical choice where standard closed-shaft drivers cannot complete the job. The 5/16 inch hex drive pairs with a heat-treated, tempered chrome-plated steel shank for durability under repeated torque loads. The yellow cushion-grip handle provides hand comfort during extended use. Licensed electricians, HVAC technicians, and plumbers routinely carry this driver as a standard hand tool on service calls.

This nut driver is suited for residential and light commercial service work where 5/16 inch hex fasteners appear frequently — including electrical panel work, equipment mounting, duct hardware, and control board brackets. The 3 inch shank length gives adequate reach into recessed fastener locations without sacrificing control. The plastic-dipped shank helps resist corrosion in wet or chemically exposed environments. It is sold individually and is also available in a pack of six for shop or van stocking.

Key Features

• Hollow shaft accepts long threaded studs and bolts extending past the nut face
• 5/16 inch hex drive size for standard trade fasteners
• 3 inch shank length for reach into recessed hardware
• Heat-treated, tempered chrome-plated steel shank for durability
• Yellow cushion-grip handle reduces hand fatigue during repetitive use
• Plastic-dipped shank for added corrosion resistance

Compatibility

Designed for use with standard 5/16 inch hex nuts and fasteners commonly found in HVAC equipment, electrical panels, and plumbing fixture hardware.

Installation Notes

Always de-energize electrical equipment before working on fasteners near live circuits. This tool is a hand driver and is not rated for use with power-drive adapters. Inspect the shank and handle for cracks or damage before each use. Consult applicable NEC or local code requirements when servicing energized enclosures.

Technical Specifications

• Drive Size: 5/16 inch hex
• Shank Length: 3 inches
• Shaft Type: Hollow
• Shank Material: Heat-treated tempered chrome-plated steel
• Handle Material: Plastic cushion grip
• Handle Color: Yellow
• Weight: 0.25 pounds

Standard Information

• Brand: KLEIN TOOLS
• Manufacturer Part Number: 640-5/16