The conical black or white board is used for detecting non-smoothness, feathering and other errors at the thread sample by winding it at predetermined extent and range. It can wind at variable speed from 8 to 19 windings per centimeter. One white conical board is given with the device as Standard. The Standard photographs ASTM which are required to compare can be supplied optionally. ASTM photographic yarn view Standard (ASTM D2255)

STANDARDS
ASTM D2255