M440 - Die Nuts M 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 M20 Pitch 2.50 Size AF 37.5