Reference tables
The tables this toolkit runs on. Print it for the gang box.
A field guide, not a lift plan.
Alloy chain — grade 80
| Size | Metric | Rated (lb) | Rated (kg) | Lower of the two |
|---|---|---|---|---|
| 7/32 in | 5.5 mm | 2,100 lb | — | 950 kg |
| 9/32 in | 7 mm | 3,500 lb | 1,500 kg | 1,500 kg |
| 5/16 in | 8 mm | 4,500 lb | 2,000 kg | 2,000 kg |
| 3/8 in | 10 mm | 7,100 lb | 3,150 kg | 3,150 kg |
| 1/2 in | 13 mm | 12,000 lb | 5,300 kg | 5,300 kg |
| 5/8 in | 16 mm | 18,100 lb | 8,000 kg | 8,000 kg |
| 3/4 in | 20 mm | 28,300 lb | 12,500 kg | 12,500 kg |
| 7/8 in | 22 mm | 34,200 lb | 15,000 kg | 15,000 kg |
| 1 in | 26 mm | 47,700 lb | 21,200 kg | 21,200 kg |
| 1-1/4 in | 32 mm | 72,300 lb | 31,500 kg | 31,500 kg |
Alloy chain — grade 100
| Size | Metric | Rated (lb) | Rated (kg) | Lower of the two |
|---|---|---|---|---|
| 7/32 in | 5.5 mm | 2,700 lb | — | 1,220 kg |
| 9/32 in | 7 mm | 4,300 lb | 1,900 kg | 1,900 kg |
| 5/16 in | 8 mm | 5,700 lb | 2,500 kg | 2,500 kg |
| 3/8 in | 10 mm | 8,800 lb | 4,000 kg | 3,990 kg |
| 1/2 in | 13 mm | 15,000 lb | 6,700 kg | 6,700 kg |
| 5/8 in | 16 mm | 22,600 lb | 10,000 kg | 10,000 kg |
| 3/4 in | 20 mm | 35,300 lb | 15,700 kg | 15,700 kg |
| 7/8 in | 22 mm | 42,700 lb | 19,000 kg | 19,000 kg |
| 1 in | 26 mm | 59,700 lb | 26,500 kg | 26,500 kg |
| 1-1/4 in | 32 mm | 90,400 lb | 39,400 kg | 39,400 kg |
Single leg, straight vertical pull, at the 4:1 design factor. Pounds are the NACM alloy grades (with ASME B30.9); kilograms are the metric series (EN 818-2 / ISO 3076). The last column is the lower of the two, and it is the one this toolkit picks from.
Then read the tag. A table narrows the choice; it does not rate the chain in your hand. Unmarked, worn, stretched, nicked, heated, welded or repaired: no rating at all.
Sling angle factors
| Angle from horizontal | Factor | What that means |
|---|---|---|
| 90° | ×1.000 | Straight up. Each leg takes its plain share. |
| 75° | ×1.035 | Barely more than straight up. |
| 70° | ×1.064 | About 6% more in each leg. |
| 60° | ×1.155 | The everyday angle. 15% more. |
| 55° | ×1.221 | 22% more. |
| 50° | ×1.305 | Nearly a third more. |
| 45° | ×1.414 | 41% more. Halfway to trouble. |
| 40° | ×1.556 | 56% more — half again as much. |
| 35° | ×1.743 | Three quarters more. |
| 30° | ×2.000 | Double. Each leg now carries the whole load’s weight. |
The standard load angle factors. Below 30° the charts stop, and so should you. The sling tension tool applies these live.
Material densities
| Material | kg/m³ | lb/ft³ |
|---|---|---|
| Concrete — reinforced | 2,400 | 150 |
| Concrete — plain | 2,300 | 144 |
| Steel | 7,850 | 490 |
| Aluminium | 2,700 | 169 |
| Lumber — dry softwood | 500 | 31 |
| Lumber — green softwood | 640 | 40 |
| Water | 1,000 | 62 |
| Soil / earth — loose | 1,300 | 81 |
| Soil / earth — compacted | 1,750 | 109 |
| Gravel / crushed rock — dry | 1,600 | 100 |
| Gravel / crushed rock — wet | 1,900 | 119 |
| Sand — dry | 1,600 | 100 |
Typical, not exact. If the number matters, weigh it or find the paperwork. The load weight estimator works from these.
Useful exact conversions
| From | To | Exactly |
|---|---|---|
| 1 pound | kilograms | 0.453 592 37 |
| 1 US short ton | kilograms | 907.184 74 |
| 1 foot | metres | 0.304 8 |
| 1 inch | metres | 0.025 4 |
| 1 cubic yard | cubic metres | 0.764 554 857 984 |
| 1 mile per hour | km/h | 1.609 344 |
| 1 knot | km/h | 1.852 |