M446 - Die Nuts UNF Sutton Tools Die Nuts are designed for cleaning and resizing existing damaged threads. Carbon Alloy Steel threading tools are not suitable for precision, safety or critical thread. General purpose / DIY use only. Hexagonal die can be used with a wrench or socket in limited space Best suited for maintenance and repair work Made from Carbon Steel Bright finish for general purpose applications, non-ferrous metals & plastics Size 5/16 TPI 24 Size AF 21