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CM (Columbus McKinnon)

USA-made CM Super Strong galvanized screw pin (M646G) and bolt-type (M846G) anchor shackles from 1/4″ to 2″ (6:1 design factor).

Technical Specifications & Rigging Reference

CM® (Columbus McKinnon) Super Strong Anchor Shackles — M646G & M846G Technical Guide

Forged in the USA by Columbus McKinnon (CM®), CM Super Strong galvanized screw pin (M646G series) and bolt-type (M846G series) anchor shackles deliver 17% to 50% higher Working Load Limits than standard carbon shackles of the same nominal body diameter while maintaining a full 6:1 design factor.

17%–50% Higher WLL Size-for-Size

Special micro-alloy steel chemistry and precision heat treatment give a 1/2" CM Super Strong shackle a 3.0 Ton WLL (vs. 2.0 Tons on standard carbon shackles) and a 3/4" shackle a 6.5 Ton WLL.

Full 6:1 Design Factor (ASME B30.26)

Every CM Super Strong shackle from 1/4" (0.75 Ton) through 2" (35 Ton) is engineered with a 6:1 ultimate-strength safety factor, meeting or exceeding ASME B30.26 and Federal Spec RR-C-271.

Hot-Dip Galvanized Bow & High-Vis Orange Pin

Available with hot-dip galvanized bows for outdoor corrosion resistance and signature CM orange alloy screw pins or bolt-nut-cotter assemblies with forged WLL, size, and USA traceability markings.

CM® Super Strong Galvanized Anchor Shackle Working Load Limit & Dimension Chart (6:1 Design Factor)
Nominal Shackle Size CM Super Strong WLL (Tons) CM Super Strong WLL (lbs) Pin Diameter Inside Bow Width Pin Styles Stocked
1/4" – 3/8" 0.75 – 1.50 Tons 1,500 – 3,000 lbs 5/16" – 7/16" 0.75" – 1.03" Screw Pin (M646G) & Bolt Type (M846G)
1/2" 3.00 Tons 6,000 lbs 5/8" 1.31" Screw Pin (M650G) & Bolt Type (M850G)
5/8" 4.50 Tons 9,000 lbs 3/4" 1.69" Screw Pin (M651G) & Bolt Type (M851G)
3/4" 6.50 Tons 13,000 lbs 7/8" 2.00" Screw Pin (M652G) & Bolt Type (M852G)
7/8" – 1" 8.50 – 10.00 Tons 17,000 – 20,000 lbs 1" – 1-1/8" 2.28" – 2.69" Screw Pin (M653G/M654G) & Bolt Type
1-1/8" – 1-1/2" 12.00 – 20.00 Tons 24,000 – 40,000 lbs 1-1/4" – 1-5/8" 2.91" – 3.63" Screw Pin & Bolt Type Safety Anchor
1-3/4" – 2" 30.00 – 35.00 Tons 60,000 – 70,000 lbs 2" – 2-1/4" 5.00" – 5.75" Screw Pin & Bolt Type Safety Anchor

Capacity Charts, Inspection Guides & Related Rigging Categories

Frequently Asked Questions

How do CM Super Strong shackles achieve a higher Working Load Limit than standard carbon shackles?
Columbus McKinnon manufactures Super Strong shackles from quenched-and-tempered micro-alloy steel rather than standard Grade 1035 carbon steel, allowing a 17% to 50% higher Working Load Limit in the exact same body and pin dimensions while maintaining a 6:1 design factor.
Are CM Super Strong shackles made in the USA?
Yes. CM Super Strong anchor shackles are domestically forged in the USA with full heat-code traceability, nominal size, and Working Load Limit permanently forged into the shackle bow.
When should I choose a CM Bolt-Type (M846G) vs. a Screw Pin (M646G) shackle?
Use Screw Pin shackles for quick-rigging picks where the pin is inspected before each lift, and choose Bolt-Type shackles (with bolt, nut, and cotter pin) for overhead suspension, long-term installations, or lifts where rotation could loosen a screw pin.
Can CM Super Strong shackles be side-loaded?
Yes, with mandatory ASME B30.26 capacity reductions: 100% of WLL for inline loading (0°–5°), 70% of WLL for 6°–45° from inline, and 50% of WLL for 46°–90° from inline. Never side-load beyond 90°.
Do CM Super Strong screw pins interchange with other shackle brands?
No. Never mix shackle pins between manufacturers or shackle grades. Always use the original factory-matched CM alloy orange pin engineered for that specific CM Super Strong bow.
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