M,  Repair Term

Metal Locking

A simple but effective method of repairing cracks in cast metals without the need for welding. The metal-locking process involves (A) drilling several lines of holes that are at right angles to the crack being repaired, then (B) inserting tight-fitting metal alloy “locks” or “keys” into the holes. Next, (C) additional holes are drilled along the crack and then filled with studs. (D) The studs are installed so each stud bites into its predecessor until the joint is pressure-tight and casting rigidity has been restored. The final step is to grind away excess metal so that the repaired surface is smooth.

Also known as Metal Stitching.

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