Crosby S-279 Machinery Eye Bolt

Crosby S-279 & M-279 Machinery Eye Bolts – Forged Steel, Fatigue-Rated, In-Line Lifting Points

The Crosby S-279 (UNC) and M-279 (Metric) Machinery Eye Bolts are precision-forged lifting points designed for machinery and equipment where a secure, in-line lifting connection is required. Each bolt is forged from quenched and tempered alloy steel, fatigue rated to 1.5× its Working Load Limit (WLL) at 20,000 cycles, and meets or exceeds ASME B30.26 requirements for material traceability, proof load, ductility, and design factor.

Key Features

Forged steel construction – quenched and tempered for strength and durability

Designed and rated for in-line loading only

Fatigue rated to 1.5× WLL at 20,000 cycles

5:1 design factor; maximum proof load = 2× WLL

Meets ASME B30.26 identification, ductility, and temperature requirements

Available in UNC (S-279) or Metric (M-279) thread sizes

Pro Tip: Crosby Machinery Eye Bolts are supplied without nuts. These bolts are primarily designed for installation into tapped holes on machinery or equipment. When used through-bolted, nuts and washers must be added so the shoulder seats flush against the load surface. Always follow Crosby’s installation diagrams and ensure the shoulder is tight before lifting.

Specifications

• Model
• Thread Type & Size Range
• Working Load Limit (WLL)
• Angular Loading Reduction
• S-279
• UNC thread, 3/8" to 2-1/2"
• 1,550 – 65,000 lbs
• 15° = 80% WLL30° = 65% WLL45° = 30% WLL90° = 25% WLL
• M-279
• Metric thread, M6 to M64
• 200 – 29,500 kg
• Note: Rated capacities apply to in-line loading only. For angular lifts, apply the reduction factors shown. All Crosby eye bolts are based on a 5:1 design factor and proof-tested to 2× WLL.
• Do not undercut the shoulder to seat flush; instead, countersink or use washers with proper inner diameter.
• Thread the eye bolt fully and tighten securely against the load surface.
• Inspect before use—never use if bent, elongated, or damaged.
• For aluminum or dissimilar metals, avoid leaving the bolt installed long-term to prevent galvanic corrosion.
• Typical Applications
• Machinery lifting, rigging, and positioning
• OEM equipment mounting points
• Industrial fabrication and maintenance lifts
• Important: Always ensure the load is applied in the plane of the eye. Angular lifts require reduced capacity and proper shimming for alignment. Refer to Crosby’s official application and warning information for complete installation guidance.

Sizes and working load limits

Prices, stock and lead times on request. Every item can be supplied with a test certificate; proof-load testing in our own test house on request.