FYI,

This quote comes from " Composite Basics" by Andrew Marshall, one of the experts in the field of composites and composite construction.

"One of the sore points in composites is the fact that most laminates, particularly the high-strength ones, are seriously degraded by drilling holes in them. The problem can show up as a substantial reduction in the part's strength. This reduction is is always much more than that represented by the loss of area due to the hole, and is accompanied by poor edge-strength of rivets or bolts that are set into the holes along the edge of the part. Also serious chafing of a bolt in the hole as it rotates or vibrates can occur, exposing the fibers in the drilled hole to the subsequent ravages of moisture and time."

Basically it is saying to be very cautious when drilling holes through composites, especially if a bolt, rivet, or other stress-producing item is inserted through the hole.


Fish on.........