Split-pin Lewis
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The Split-Pin Lewis is similar to the Chain-Linked Lewis in that it uses a scissor-like action to produce friction against the inside of the Lewis hole. The two legs, however, are joined by a hinge-pin, lie side-by-side, and are shaped to fit inside a 20mm diameter hole drilled to a minimum depth of 82mm.
This type of Lewis seating is the simplest to prepare, requiring a single drilled hole.