Bolt
Wood screw
Stud
Nut
.
Length of the taper
Length of the job
Amount taper
Length of offset
Remove induced stresses
Improve machinability
Soften the steel
Increase the toughness and reduce brittleness
High carbon steel
Cast iron (heavy parts)
Low carbon steel parts
Alloy steel parts
Cyaniding
Gas nitriding
Carburizing
Induction hardening