دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: a short piece of pipe with a pronounced upset, or shoulder, on the upper end, screwed into drill pipe, drill collars, or casing to provide a positive grip for the elevators. Also called a lifting sub or a hoisting plug.

n: a tool that used to hoist and lower non-cog bit..