a. A short tubular piece designed to couple a bit to a core barrel. The
outside surface of the reaming shell is provided with inset diamonds or
other cutting media set to a diameter to cut a specific clearance for the
core barrel. See also: reamer; reamer shell. Syn: reaming ring Long
b. Sets of two or more shells that are alternated every 50 ft (15.24 m) to
keep loss in gauge to the hole uniform. The shell is changed when wear
reaches 0.012 in (0.03 cm) below the original set diameter.
Dictionary of Mining, Mineral, and Related Terms