Hoist Rings Information
Hoist rings are load-centering eyebolts. They are designed to be rigged from the center or the side and may pivot or swivel. Some hoist rings connect directly to webbing, chain, or shackles. Others have a hook-end rather than a standard bail, eye, or ring. Basic types of hoist rings include:
Center-pull hoist rings are designed to be rigged from the center and should not be set up to be pulled from the side.
Side-pull hoist rings are designed to be rigged from the side and should not be set up to be pulled from the center.
Screw-mount lifting rings are hoist rings with a fixed base. They have mounting holes for screws. In terms of movement, pivoting hoist rings have an eye that is designed to pivot 180°.
Product specifications for hoist rings include:
- Maximum load capacity
- Threaded length
- Overall bail length
- Overall bail width
- Bail radius
- Bail thickness
Metallic hoist rings can be made of:
- Aluminum - Lighter than steel, but not as strong.
- Brass - Common copper-base alloy.
- Bronze - Common copper-base alloy.
- Steel and hardened steel - Many different grades of carbon steel and alloy steel are used as fastener materials.
- Stainless steel - Stainless steel may not require anti-corrosion coatings, but cannot be hardened to the same degree as carbon steels.
- Titanium - A metal that is used widely in the aerospace industry, titanium is suitable for specialized applications.
- Proprietary alloys
In terms of finish, hoist rings are often:
- Plated with gold, silver, tin, or zinc.
- Coated with black oxide which causes virtually no dimensional change.
- Coated with phosphate which provide corrosion resistance and a better surface for the adhesion of primers and paints.
- Finished with zinc chromate.
Thread sizes for hoist rings are measured in English units such as inches (in) or metric units such as millimeters (mm).
Inch-based measurements for rings include:
- 1 1/8"
- 1 1/4"
- 1 3/8"
- 1 1/2"
- 1 3/4"
- 2 1/4"
- 2 1/2"
- 2 3/4"
Fasteners designated as #16, #18, #20, #24 hoist rings are also available.
Metric designations for hoist rings include:
As a rule, the numbers which follow the letter “M” indicate the number of millimeters in diameter. For example, an M6 hoist ring is 6 mm in diameter.
MS 15366 - Rings, connecting, round, hoisting sling, marine hardware