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These key-locking threaded inserts are ideal for thread reinforcement, especially when the mating stud or bolt will be removed frequently. They provide strong, permanent steel threads in a weaker parent material — ferrous, non-ferrous, or non-metallic. Key Inserts are also well suited for quick repair of stripped, damaged, or worn threads. A solid version is also available to use as a handy plug to relocate holes drilled or tapped on the wrong location. Install with standard drills and taps. Important: Use tap drill specified in table (slightly larger than standard for that thread size). Tap-drill hole tolerance should be -.001/+.004 (-.001/+.005 above .500 dia).

Locking keys are driven down into the parent material during installation, providing a positive mechanical lock against rotation. Inserts with an ID thread 5/16 and above have four locking keys, smaller sizes have two. Pull-out strength can be calculated approximately by the following formula:

Key Inserts are often used to reinforce tapped holes
in aluminum tooling plates.

Easy Installation
  1. Drill out old threads using tap drill specified in table (Important: Correct tap drill is slightly larger than standard for that thread size).
  2. Countersink to diameter shown in table.
  3. Tap new threads, using standard tap.
  4. Screw in insert until body is slightly (.010 to .030 inches) below the surface, by hand or using installation tool. Keys act as a depth stop.
  5. Drive keys down with several light hammer taps on installation tool (or directly on keys if no installation tool is available).

Easy Removal
  1. Drill out locking keys with specified drill diameter and depth (see table).
  2. Deflect keys inward and break off.
  3. Remove insert with an E-Z OUT type tool.
  4. Screw replacement into original holes. Parent material is totally undamaged.