How to Splice Wire Rope: Flemish Eye and Return Loop Methods

Why Splice Wire Rope?

A properly made wire rope splice retains 95-100% of the rope’s rated breaking strength — significantly more than any knot (which typically reduces strength by 40-60%) and comparable to mechanical swaged fittings. Splicing creates a permanent, smooth eye in the rope end that accepts thimbles, shackles, and hooks without the bulk of clamp assemblies.

Splice Types Overview

Splice Type	Strength Retention	Difficulty	Tools Required	Best Application
Flemish Eye (Molly Hogan)	95-100%	Advanced	Spike, pliers, seizing wire, thimble	Permanent rigging, crane pendants, guy wires
Return Eye (Tuck Splice)	80-90%	Intermediate	Spike, pliers, seizing wire, thimble	General rigging, temporary eyes
Wire Rope Clips (U-bolt)	80%	Easy	Wrench, clips, thimble	Field terminations, adjustable connections
Mechanical Swage	95-100%	Requires press	Swaging press ($5,000+)	Manufacturing, high-volume production

Flemish Eye Splice — Step by Step

The Flemish eye (also called a Molly Hogan splice) creates the strongest hand-made termination by unlaying the rope into two groups of strands, forming a loop, and relaying the strands together. The result looks like the original rope with an eye formed in the end.

Tools Needed

• Marlinspike or fid (sized for your rope diameter)
• Wire rope cutters (NOT bolt cutters — they crush the wires)
• Seizing wire (soft annealed iron wire)
• Pliers or vise grips
• Thimble (sized for your rope diameter)
• Safety glasses and leather gloves

Procedure

1. Seize the rope at the point where the eye will begin. Apply a tight serving of seizing wire, at least 3 rope diameters long.
2. Unlay the strands from the end back to the seizing. Separate into two groups of 3 strands each (for 6-strand rope).
3. Form the eye: Bring the end of the rope back to form the desired eye size. Insert the thimble.
4. Relay the strands: Interleave the unlaid strands with the standing rope strands, recreating the rope lay. Each strand from group A goes between two strands of the standing part, alternating with strands from group B.
5. Work the strands tight: Use the spike and pliers to pull each strand into its groove, maintaining the original rope lay pattern.
6. Seize the splice: Apply seizing wire at the throat (where the eye meets the body) and at the end of the splice.
7. Cut excess wire: Trim protruding wire ends flush and cover with tape or serve with seizing wire to prevent snagging.

Return Eye Splice (Tuck Splice)

The return eye splice (also called a Liverpool splice or tuck splice) is simpler than the Flemish eye but retains less strength (80-90%). Individual strands are tucked under standing strands in a pattern similar to fiber rope splicing.

Procedure

1. Seize and unlay approximately 6-8 rope diameters of strands from the end
2. Form the eye around the thimble at the desired point on the standing rope
3. Tuck each strand under one standing strand, working against the lay direction. The first tuck is the most critical — each strand must go under the correct standing strand.
4. Complete 3-4 full tucks for each strand. Each tuck goes under the next standing strand in sequence.
5. Taper the splice (optional but recommended) by cutting half the wires from each strand after the 3rd tuck, then all remaining wires after the 4th tuck. This creates a smooth transition.
6. Seize and trim as with the Flemish eye.

Wire Rope Clips — The Field Method

When splicing isn’t practical (field conditions, temporary connections, or lack of splicing skills), wire rope clips (U-bolt clips) provide an 80% efficient termination.

Number of Clips Required

Rope Diameter	Minimum Clips	Spacing (6 × rope diameter)	Torque (ft-lbs)
1/4″	2	1-1/2″	15
3/8″	2	2-1/4″	30
1/2″	3	3″	45
5/8″	3	3-3/4″	65
3/4″	4	4-1/2″	95
7/8″	4	5-1/4″	95
1″	5	6″	130

Installation Rules

• “Never saddle a dead horse”: The U-bolt (saddle) goes on the dead (short) end. The base (saddle plate) goes on the live (loaded) end. Putting the U-bolt on the live end crushes the load-bearing wires.
• Turn back length: Minimum 6 inches or one clip spacing, whichever is greater
• Re-torque after loading: After the first load application, re-torque all clips to specification. Repeat after 2-3 additional load cycles.

Thimble Selection

Always use a thimble in the eye of a wire rope splice. The thimble protects the rope from crushing and abrasion at the bend point.

• Standard thimbles: Light duty, adequate for most applications
• Heavy-duty thimbles: Thicker walls, used for high-cycle applications and larger ropes
• Stainless steel thimbles: For marine and corrosive environments
• Sizing: The thimble groove must match the rope diameter. An oversized thimble allows the rope to flatten; undersized crushes the rope.

Safety Considerations

• Wire rope is dangerous to handle: Broken wires act as needles. Always wear leather gloves and safety glasses.
• A splice is only as good as the splicer: Improperly made splices can fail at a fraction of rated capacity. If you’re not confident in your splicing ability, use mechanical terminations.
• Inspect splices regularly: Look for wire breakage near the throat of the eye, thimble displacement, and loosening of the splice body.
• Never splice wire rope that shows signs of fatigue, corrosion, or damage: Splicing a damaged rope doesn’t restore its strength.

Common Mistakes to Avoid

Avoiding these common errors can prevent equipment failure, regulatory violations, and serious safety incidents in the field.

• Ignoring the Fleet Angle: The angle between the wire rope and the drum or sheave should not exceed 1.5 degrees for smooth drums or 2 degrees for grooved drums. Excessive fleet angles cause uneven spooling and accelerate wear, reducing service life by up to 50%.
• Using Undersized Sheaves: The sheave diameter should be at least 18-20 times the rope diameter. Undersized sheaves cause severe bending fatigue. A 1/2-inch rope requires sheaves of at least 9-10 inches in diameter.
• Failing to Lubricate Properly: Wire rope requires regular lubrication to prevent internal corrosion and reduce friction between wires. The lubricant must penetrate to the core. Use wire rope lubricants specifically designed for the application, not general-purpose grease.
• Improper Dead-End Termination: Using fewer than the required number of clips, or installing U-bolt clips with the saddle on the dead end, can reduce termination efficiency to as low as 40%. Follow the Crosby clip spacing chart for correct number and torque values.
• Ignoring Broken Wire Criteria: ASME B30.9 requires rope retirement when 6 randomly distributed broken wires are found in one rope lay, or 3 broken wires in one strand in one lay. Continuing past these thresholds risks catastrophic failure.