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Superbolt® Flexnuts

Enhance bolt or stud longevity by alleviating stress concentrations with Superbolt Flexnuts, increasing fatigue life and ensuring long-term reliability.

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  • Flexnuts
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REACTIVE SIDE SOLUTIONS

Superbolt developed the Flexnut for through-hole applications. Flexnuts bring the advantages of MJT-type elasticity to the reactive side of the joint.

Flexnuts are designed to flex out at the bottom and flex in toward the top of the nut. This distributes the bolt load along many threads, adds elasticity, and prevents stress concentrations in the first few threads.

Flexnuts are reactive nuts, designed to be applied opposite Superbolt tensioners. They are never torqued directly to achieve preload.

Additional information

Advantages

  • Ensures an equal load distribution on the thread of the bolt/stud, under load
  • Adds elasticity in the joint
  • Increases the fatigue life of the bolt/stud

Specifications

Standard series

Flexnut type Specifications
SX8
Standard Flexnut
  • Dimension range: M20 - M160 (3/4″ - 6″)
  • Approx. bolt stress depending on size: 450 to 700 N/mm2 (60 to 100 ksi)
  • Temperature range: -10 to 250ºC (0 to 500ºF)

SX12
High-strength Flexnut

  • Dimension range: M20 - M160 (3/4″ - 6″)
  • Approx. bolt stress depending on size: 500 to 900 N/mm2 (70 to 130 ksi)
  • Temperature range: -10 to 250ºC (0 to 500ºF)

Technical drawings

Technical drawings

Download

View

  • Superbolt Tensioners Dimension Sheet - SX12 Metric.pdf

  • Superbolt Tensioners Dimension Sheet - SX12 UNC.pdf

  • Superbolt Tensioners Dimension Sheet - SX8 Metric.pdf

  • Superbolt Tensioners Dimension Sheet - SX8 UNC.pdf

  • Tensioning application checklist.pdf

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