Handling of Wire Rope
When handling wire rope, be sure to use the correct rope lay direction for the drum. This applies to smooth, as well as to grooved drums.
When overwinding or underwinding the rope, use your hand opposite from the direction you are pulling the rope.
If you are in doubt about this issue or require further assistance, please call us at Cable Craft and we will be happy to assist you.
Drum & Reel Capacities
To calculate the maximum length in feet of steel wire rope which a specific drum or reel will hold under normal tension and uniform winding conditions, the following formula applies to help you figure out the capacity:
(C + D) x D x W x FACTOR
To understand this formula clearly, here is a breakdown of the formula:
W – Inside width of drum
C – Core of drum
D – Depth of flange
1. Add diameter of core (C) to depth of flange (D)
2. Multiply the sum by the depth of flange (D)
3. Multiply the result by the inside width of drum (W)
4. Multiply the result by the factor (F)
RESULT – Drum capacity of wire rope in feet
The fleet angle is the included angle between two lines: one line drawn through the middle of the fixed sheave and the drum – perpendicular to the axis of the drum – and a second line drawn from the flange of the drum to the base of the groove in the sheave.
There are left and right fleet angles, measured to the left or right of the center line of the sheave.
Wire Rope Problems
Wire Rope Problems can be any of the following issues:
1. Accelerated Wear – Caused by severe abrasion, poorly aligned sheaves and contact pressures
2. Rapid Appearance of Broken Wires – Caused by overload, crushing of rope or small sheaves
3. Corrosion – Caused by inadequate lubrication, improper storage or exposure to acids or alkalis
4. Kinks – Caused by improper installation and handling and slack rope pulled tight
5. Excessive Localized Wear – Caused by drum crushing or equalizing sheave
6. Stretch – Caused by overload or passed normal stretch and approaches failure
7. Broken Wires near Fitting – Caused by rope vibration or fittings are pulled too close
8. Sheaves/Drums wear out – Caused by the material becoming too soft
9. Pinching, Crushing or Oval Shape – Caused by small sheave grooves or improper installation
10. Rope Unlays or Opens up – Caused by wrong rope construction
11. Reduction in Diameter – Caused by broken core, overload, internal wear and corrosion
12. Bird Cage – Caused by tight sheaves, shock loads or improper wedge socket installations
13. Core Protrusion – Caused by shock loading, disturbed rope lay and load spins and rotations
Web Sling Inspection
When a web sling goes through the inspection process, it is examined for several visible things.
If the following things are found during the inspection, the sling will be removed from service:
1. If the sling rated capacity tag is missing or not readable
2. Acid or alkalis burns
3. Melting, charring or weld spatter of any part of the sling
4. Holes, tears, cuts, snags or embedded particles
5. Broken or worn stitching in load bearing splices
6. Excessive abrasive wear
7. Knots in any part of the sling
8. Distortion, excessive pitting, corrosion or broken fittings
9. Any conditions which cause doubt as to the strength of the sling
Wire Rope Inspection
The wire rope inspection is a more complex procedure because there are no precise rules to determine exactly when a wire rope sling should be replaced.
The following things would remove the wire rope from being used:
1. Broken wires
2. Metal loss
4. Heat Damage
5. Bad End Attachments
6. Bent Hooks
8. Pulled Eye Splices
9. Mechanical Damages
Chain Sling Inspection
Chain slings should be inspected according to two schedules: daily (or before use) and periodically.
For daily inspection, the following should be looked for and considered:
1. Ensure the chain is alloy steel and the correct grade is either 80 or 100
2. Ensure the tag displaying the WLL is on the chain and specifies a 5-to-1 safety factor
3. Check individual links for signs of damage such as stretching, bends, twists, cracks, gouges, and corrosion
4. Check overall condition of the chain for knots, kinks, stretch and whether or not the chain hangs straight
5. Check hardware for deformity, nicks, cracks, gouges, and other signs of wear or abuse
6. Hooks must have positive locking latches and openings within tolerance
7. Master links must be in good conditions
For periodic inspection, the following should be looked for and considered:
4. Defects in hardware
Damaged chain must not be repaired by welding or heating since high heat will alter the properties and strength of the chain.