A system and method for joining together a pair of brittle material pieces, such as controlled expansion ceramic pieces, involves using a threaded plug joined to a first brittle material piece, to secure a threaded fastener passing through part of the second brittle material piece, thus joining together the brittle material pieces. The threaded plug may be inserted in a plug-receiving hole that may be substantially perpendicular to a fastener-receiving hole in the first brittle material piece. One or both of the plug and the plug-receiving hole may be conical, to facilitate fitting the plug into the plug-receiving hole. The plug may be secured to the first brittle piece by soldering. The system and method provides a secure way of threadedly joining together a pair of brittle material parts, without use of possibly contaminating adhesives, and without a need to put threads on the actual brittle material itself.