- Different company's use different numbering conventions. Robline uses the diameter in millimeters times 10. The others pull numbers out of the air.
- Strength data is seldom published. The few data points I've found seem accurate, but mostly thread manufactures expect you to guess. Just pitiful.
For polyester twine, some average values:
Robline #4 0.4mm 10 pounds
Robline #6 0.6mm 21 pounds
Robline #8 0.8mm 50 mounds
Robline #10 1.0 mm 90 pounds
Robline #15 1.5 mm 180 pounds
If it is important to you...
- Make a loop with a fishermans bend or other strong knot.
- Wrap the line around a broom stick such that the knot is 1 1/4 wraps around from the start. Add another 1 1/4 wraps. In this way, the knot will not break.
- Hang 2-4 passes over a pull up bar and stand on a bathroom scale. Read how light you are when it snaps, subtract, and divide by the passes.