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Thread Repair Technical Information

Shop All Thread Repair
Free Running Screw Locking Tangless
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Basics of...Thread Repair
Keylocking Self-Locking

Thread Repair Inserts are used to quickly and permanently restore tapped holes, which have been stripped or damaged due to wear, corrosion or over torque.

4 Easy Steps for Coil Type Inserts

Drill- Drill hole
Tap- Tap the hole to a sufficient depth to accommodate the insert length and bolt being used
Install- Install the appropriate length insert. Use the installation tool and wind the insert into the hole until the top coil is ¼ - ½" below the surface
Tang Removal- Remove the tang by using a break-off rod or a punch that fits inside the insert

Coil Type Inserts

Free Running

  • Can be used to repair tapped holes, which have been stripped or damaged due to wear, corrosion or over-torque
  • Coil tension holds insert in place without placing tension on surrounding material
  • Vibration & impact resistant

Free Running

  • Features a locking mechanism that grips the bolt and prevents it from loosening under vibration or impact
  • Eliminates the need for thread locking mechanisms
  • Allows repeated assembly and disassembly without appreciable loss of selflocking torque


  • Tangs must be removed to eliminate interference with the end of the assembled bolt
  • Operation is automatic and can be operated with one hand
  • Tang break off tool is required


  • Eliminates the need for a tang break-off tool
  • Installs quickly and easily from either end

Strip Feed Reels

  • Bulk inserts mounted on plastic strips available in reels of 500 or 1000
  • Increases installation rates by minimizing handling
  • Used with power installation tooling to support high volume production requirements

Surface Treatments for Coil Type Inserts

Primer Free II®

  • Contains no chromates; RoHS compliant
  • Eliminates need for zinc primer
  • Prevents galvanic corrosion between insert and parent material
  • Eliminates locking torque issues associated with primers
  • Improves installation productivity
  • Provides additional lubrication facilitating insert installation

Gall Resistant

  • Material: Nitronic 60
  • Requires no additional coatings or plating
  • Non-magnetic & particle free
  • Ideal for use in vacuum environments

Dry Film Lubricant

  • Provides additional lubrication in high friction applications
  • Temperature resistant up to 400° F
  • Contains corrosion resistant properties

Thread Repair Kits

  • A convenient way to quickly repair tapped holes which have been stripped or damaged
  • Most kits (unless otherwise noted) contain: Drills, taps, installation tools, tang break-off tools and a quantity of inserts
  • Available in Inch, Metric, Spark Plug or Pipe Thread series


Hand Installation

  • Used to install inserts in tapped holes
  • Thread size of the insert to be installed will determine the choice of tool:

    To install coarse threads use a Mandrel
    To install fine threads use a Prewinder

Hand Extraction

  • Used to remove inserts from a tapped hole
  • Place tool inside hole with insert to be removed. Strike head of the tool with a light blow and turn counter clockwise, maintaining steady downward pressure

Tang Break-Off

  • Removes tang after installation to prevent interference with the end of an assembled bolt
  • Available for use with sizes up to 1/2" and M12 nominal diameter


  • Used for high volume production
  • Can be hand held or mounted on a work station
  • Consists of an air motor, adapter and front end assembly
  • Available for use with sizes up to 1/2 and M12 nominal diameter
  • Front end assembly consists of:


Screw Thread Insert (STI) Taps

  • For use in tapping holes according to screw thread standards


Carbon Steel

  • Standard, general purpose material

Stainless Steel

  • Corrosion resistant
  • Ideal for original equipment applications, repair and overhaul


  • Superior strength to weight ratio
  • Corrosion resistant
  • Excellent low pressure stability

Nitronic 60

  • Compatible with stainless steel screws
  • Ideal for vacuum environments
  • Particle-free, non-magnetic with excellent gall resistance

Non-Coil Type Inserts


  • Designed to fill holes that are too large or relocated holes that have been drilled or tapped in the wrong location


  • Repairs stripped or worn threads in jigs, fixtures, bolster plates, dies and machine tools
  • Features a locking element to hold insert secureley in place and will not loosen under vibration


  • Features 2 or 4 locking keys that provide superior holding power in a variety of materials
  • Inserts with internal threads of size M7 or larger are furnished with 4 locking keys, sizes smaller than M7 are supplied with 2 locking keys

Solid Thread Insert Styles

Thin Wall- Designed for applications where wall thickness or weight is not an issue
Heavy-Duty- Most commonly used insert, available with coarse and fine threads
Extra Heavy-Duty-Designed with increased wall thickness and greater external thread area for superior pull-out strength and holding power. In high sheer strength materials: provides comparable holding power to heavy inserts. In low sheer strength materials: provides maximum holding power and pull-out strength

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