Gibraltar HKS-2517A-G Steel Thumb Screw 1/4-20 Lobed Head

Product Description

The GIBRALTAR HKS-2517A-G is a lobed-head thumb screw designed for hand-tightening applications where tool-free fastening is required. The screw features a C-12L14 free-machining steel shank with a black oxide finish for mild corrosion resistance, paired with an aluminum lobed head that provides a secure grip for frequent adjustments. At 2-5/8 inches overall length with a 1/4-20 UNC thread, this fastener suits panel retention, machine guards, access covers, and adjustable fixtures common in industrial and commercial maintenance environments. The shouldered design keeps the fastener positively located during assembly and removal.

This thumb screw is suited for light industrial, MRO, and commercial service applications where repeated hand access is needed without tools. Typical uses include equipment enclosure panels, jig and fixture adjustment points, and machine access covers. The lobed aluminum head provides a large gripping surface across the 1-1/2 inch head diameter, reducing operator fatigue during repetitive tightening cycles. Electricians, HVAC technicians, and general maintenance trades commonly use lobed thumb screws on control panel covers and access doors.

Key Features

• 1/4-20 UNC thread on a C-12L14 free-machining steel shank for smooth, consistent thread engagement
• Lobed aluminum head at 1-1/2 inches diameter enables hand-tightening without tools
• Black oxide finish provides mild corrosion resistance and reduces light glare on exposed fasteners
• With-shoulder design keeps screw captive or positively located in mating hardware
• Flat tip suitable for standard through-hole and blind-hole threaded applications
• 2-5/8 inch overall length accommodates moderate panel stack-up thickness

Compatibility

Designed as a direct-fit thumb screw for standard 1/4-20 UNC threaded inserts, weld nuts, and through-holes in panel and enclosure applications requiring tool-free fastener access.

Installation Notes

Hand-tighten only — do not drive with power tools, as the aluminum head is not rated for tool torque. Ensure the mating thread is clean and free of debris before engagement to avoid cross-threading the steel shank. Where used on electrical enclosures, verify the installation complies with applicable NEC requirements for panel access and bonding continuity. Inspect the black oxide finish periodically in high-humidity environments and apply a light oil film if surface rust appears on the shank.