Impact Socket 1" to 21 mm Square 4‑Point JCB (model JCB-4819021)

JCB impact socket model JCB-4819021 converts a 1" drive to a 21 mm square output in a 4-point configuration. This hardened impact socket is designed for use with impact wrenches and heavy-duty power tools, providing a secure fit for square-headed adapters and fasteners while transferring torque reliably. The socket is built for repeated impact use in demanding environments such as automotive repair, construction sites, and industrial maintenance.

Advantages

The hardened construction resists deformation and wear under repeated impact loading, maintaining engagement with mating tools and fasteners. A precisely machined 4-point square interface ensures positive torque transfer and reduces the risk of rounding square drive interfaces. Compatibility with a 1" drive impact tool makes it a practical adapter for heavy-duty applications where larger torque and robust connections are required.

Suitable for

• Automotive repair and wheel service where high torque is needed
• Construction and heavy equipment maintenance
• Industrial assembly and disassembly using impact tools
• Workshops that require durable impact-rated adapters

Key specifications

• Drive input: 1" square
• Output size: 21 mm square, 4-point configuration
• Material: hardened impact-grade steel
• Intended use: impacts and heavy-duty torque transfer

How to use

Fit the 1" drive of your impact wrench or breaker bar into the socket's input and ensure it clicks or seats fully. Align the 21 mm square output with the mating square fastener, adapter, or retaining accessory and apply torque using short bursts when operating an impact wrench. Inspect the socket before use for cracks or excessive wear; replace if any damage is present. Use proper safety equipment, including eye and hand protection, when operating impact tools.

Usage recommendations

Use this impact socket only with impact-rated tools and accessories. Avoid using cheater bars or non-impact hand tools with this adapter to prevent unsafe loading. Store in a dry tool chest to limit corrosion and periodically clean and lightly lubricate interfaces to ensure reliable engagement.