Originally Posted by
FBinNY
Since you asked, 6mm has long been the closest thing to a standard for brake cable adjusters, so the stop was drilled to accommodate that. I don't know of any adjusters that measure 6.8mm, or threads that size, but if you want to use those, reaming the stop seems to be the only option (if there's enough material that strength wouldn't be sacrificed).
The adjuster is SRAM; an Avid Shorty Cantilever brake. Definitely 6.8MM. Anyway I realized the thing to do might be just put the cable end in there minus barrel adjuster. Appreciate the response.