Kaus | A4 | M8247

Stainless steel thimble A4 for wire rope and rope in A4 / AISI 316 stainless steel is intended for use in demanding environments where high corrosion resistance and mechanical protection are required. The product is used to form and reinforce loops in both wire rope and rope, which reduces wear and deformation under load. The design provides a smooth radius that distributes the load and protects the material from point loading and abrasion. It is suitable for installations where a long service life and maintained function in connections are crucial.

FIELD OF APPLICATION

The product is used in marine rigging, mooring, lifting applications, wire and rope systems, as well as structural construction. It is intended for applications where loops in wire or rope are required, for example in combination with wire rope clips, splices, or swage sleeves. The thimble protects at attachment points such as shackles, hooks, or bolts and ensures that the load is distributed correctly without damaging the wire or rope. The choice of material provides resistance to salt water, moisture, and chemically aggressive environments.

TECHNICAL SPECIFICATIONS

Product type: Hardware
Product family: Thimble
Material class: A4
Strength class: Not specified
Standard: Not specified
Item number: M8247
Diameter: 4–20 mm
Design: For wire rope and rope
Surface finish: Untreated
Environment: Marine
Delivery unit: Piece

FREQUENTLY ASKED QUESTIONS (FAQ)

What is a thimble and why is it crucial when creating wire rope loops?

A thimble is a grooved metal profile that is inserted inside a loop on a wire rope or a line:

• Prevents abrasion and chafing: When the loop is connected to shackles, hooks, or eye bolts, the thimble absorbs all friction and point loading, protecting the wire's individual strands from wearing through.

• Maintains the wire's natural bend radius: Without a thimble, the loop flattens under heavy load, creating sharp bending angles that drastically reduce the wire's actual breaking load.

• Even force distribution: The oval teardrop shape distributes the pulling force smoothly over the entire curvature of the loop.

Why is acid-resistant stainless steel A4 (AISI 316) required for thimbles in rigging and marine environments?

In rigging and marine applications, the thimble is constantly exposed to water, salt, and high mechanical stress:

• Maximum protection against crevice corrosion: Because the wire sits tightly pressed into the thimble's groove, narrow crevices are formed where moisture and salt become trapped. The molybdenum content of the A4 steel prevents pitting and crevice corrosion under the wire groove.

• Withstands coastal areas and chemicals: A4 steel is the obvious choice for standing rigging on sailboats, lifting devices on docks, offshore, and in the chemical industry.

• Galvanic compatibility: When the thimble is used together with stainless steel wire rope (A4), the risk of galvanic corrosion between the wire and the thimble is eliminated.

How do you choose the right size of thimble and how do you install it safely?

1. Dimension according to the wire diameter: The size of the thimble indicates the maximum wire diameter that fits in the outer groove (e.g., a 6 mm thimble should be used for a 5–6 mm wire). The wire should sit firmly in the groove without tilting.

2. Combine with wire rope clips or swage sleeves: Pull the wire tightly around the thimble and secure the loop with A4 stainless steel wire rope clips or crimp a copper/stainless steel sleeve.

3. Positioning of wire rope clips: When securing the loop, the first wire rope clip should be placed directly next to the pointed end of the thimble so that the thimble is completely locked in place and cannot fall out if the load is released.