riffler

from The Century Dictionary.

• noun A kind of file with a somewhat curved extremity, suitable for working in small depressions.
• noun A workman who uses such a file, especially in metal-work.

from the GNU version of the Collaborative International Dictionary of English.

• noun A curved file used in carving wool and marble.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A mechanical device consisting of a metal box with a series of vertical slats through which material is poured and randomly divided into two samples; this process is repeated to obtain a small representative sample of a bulk material
• noun A curved file used in carving wood and marble.