23.10 SAFE USE OF RIGGING SCREWS AND TURNBUCKLES

In addition to any specific instructions relating to the safe use of the rigging screws issued by the manufacturer, the following points should be observed:

  1. Never exceed the SWL for the particular mode of use.

  2. When used in a multi-leg assembly, an allowance must be made for the angle of the sling leg to the vertical.

  3. Take care to ensure that it is compatible in size with any mating equipment.

  4. Rigging screws should be fitted in a manner that allows the body and end terminations to align straight along their centre line, and not in a way that bending loads are induced. They should not be used in slinging applications where they are likely to become bent, e.g. positioned around the corner of a load.

  5. The terminal fittings must be fully screwed through the female threads. A minimum length of at least 1.6 times the thread diameter should be maintained within the body at each end.

  6. The inspection hole (if available) in the rigging screw body should be kept clear so that the position of the screw of the terminal fitting relative to the body can be seen. Where there are no viewing /inspection holes it is advisable to remove the end termination and measure the length of screwed shank to verify the minimum length of thread required for adequate and safe engagement.

  7. The plain length of the bolt fitted to a screwed fork should be long enough to ensure that the securing nut seats on the shoulder of the thread and not against the side of the fork body.

  8. Never replace the bolt of a screwed fork with anything other than an identically dimensioned and rated bolt.

  9. When tensioning rigging screws, torque should be applied by means of a short bar. A long bar or an extension to the bar should not be used.

  10. Hexagon-ended turnbuckle bodies should be tensioned by the use of a spanner on the hexagonal end.

  11. If locknuts are fitted, they must be securely tightened following the final adjustment. Care should be taken not to over-tighten locknuts. The security of all locking devices should be regularly checked.

  12. Rigging screws and turnbuckles should not be used in applications where they are liable to be unscrewed, e.g. by the rotation of a wire rope or load.