- design simple inserts with undercuts for pull-out retention and grooves or knurls for torque retention
- avoid sharp corners
- use brass, stainless steel or plated steel inserts; raw steel inserts may rust
- use clean inserts to safeguard optimal interfacing between the metal and the thermoplastic (free from oil, grease, etc.)
- ensure that adjacent walls have sufficient thickness to prevent the insert from being pulled out during assembly
- keep knurls away from part edges for notch sensitivity.