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Self-Tapping Screws
Self-tapping screws are often used to fasten plastic parts together. Self-tapping screws are available both in thread-cutting type as well as thread-forming type.
 
Thread Forming
Pros Cons
High tensile values High hoop stress, boss has to be designed to withstand this stress
High amount of torque to strip threads
Large number of cycles of assembly and disassembly possible Stress relaxation possible
Suitable for plastics that are non-brittle Not suitable for brittle plastics
 
Thread Cutting
Pros Cons
Lower Hoop Stress Lower Tensile Pullout
Suitable for brittle plastics Lower amount of torque to pull the threads