Rigging hooks can come in many variations, so it’s best to understand some of the basics of hooks and fabrications. We’ve outlined some information below, and suggest contacting our sales specialists with any other questions you may have. You can reach us at 800-660-3585 from 8am to 5pm Central Standard time.
- Grab hook: Designed to “grab” to keep a chain from slipping off the hook.
- Slip hook: Generally had a wider throat than grab hooks and sometimes has a latch design to keep an attached object in its place.
- Clevis hook: Designed with a clevis and bolt or pin at the base to create a secure way to fasten the hook to a bracket or chain.
- Self locking hook: When used within the working load limit guidelines, a self locking design ensures the hook will not open when under heavy load.
Important terminology for rigging hooks
- Grade 100 alloy: This indication refers to the tensile strength of metal. A grade 100 hook will provide approximately 25% high working load limits than Grade 80 metal.
- Type 316 stainless steel: This “marine grade” metal has better corrosion resistance to salts, chemicals and acids, particularly marine environments that involve immersion or spray of sea water
- Galvanized: Metal is finished with a thin coating of zinc to protect against rust and provide resistance to corrosion.
- Working Load Limit: Sometimes also called Rated Capacity, Rated Load Value, Resulting Safe Working Load, or Safe Working Load. It may also be abbreviated as WWL or SWL or SWWL. A Working Load Limit is the maximum weight that should be applied to the item when in use. This number is based on ideal working and environmental conditions, so if you are using the equipment in conditions out of the norm (extremely high or low temperatures, chemical vapor or solution contact, immersion over time in salt water, acids, etc.), this limit may not be correct and special precautions should be taken *A Working Load Limit should never be exceeded.*
- Break Strength: Break Strength is the amount of force used when equipment was found to break during testing at the manufacturer. It’s important to keep in mind that testing is done in a controlled environment with ideal conditions. Real life applications will involve different factors, forces and environmental conditions, so it’s best practice to follow the Working Load Limit guideline, which is generally 1/3 of the break strength.
A hoist hook undergoes extensive pressure, so it’s important to inspect them carefully and often for damage, cracks, bending and straightening. Hooks are often stamped with numbers to indicate the load information and rating of the device, making it easy to check the hook for integrity and any damage that might have occurred.