1. FASTENERS BY ROB SHAFFER JAMES BURROWS

2. OBJECTIVE EXPLAIN THE USE OF: ► MACHINE SCREWS AND NUTS ► MACHINE SCREWS AND INSERTS ► SELF THREADING/CUTTING SCREWS AND PLASTIC BOSS ► THREAD FORMING SCREWS

3. PRESENTATION RESULTS ► UNDERSTAND USE OF FASTENERS ► UNDERSTAND DIFFERENT TYPES ► APPLICATIONS

4. MACHINE SCREWS, NUTS AND WASHERS ► USE WHERE APPEARANCE IS NOT CRITICAL ► HOLES CAN BE COUNTERSUNK ► DEFLECTION, CYLENDRICAL BOSSES ► HEX SHAPE CAN BE MOLDED INTO PART

5. MACHINE SCREWS, NUTS AND WASHERS ► DISADVANTAGES  MANY PARTS REQUIRED FOR ASSEMBLY  ACCESS TO BOTH TOP AND BOTTOM OF PART  LOCKING WASHERS

6. DISADVANTAGES OF MACHINE SCREWS, NUTS AND WASHERS ► ROTATION MOTION ► REMOVED FOR RECYCLING OR GRANULATION PURPOSES

7. MACHINE SCREWS, NUTS AND WASHERS ► ADVANTAGES  DURABLE ASSEMBLY  EASILY DISASSEMBLED  EASILY REASSEMBLED

8. MACHINE SCREWS WITH A THREADED METAL INSERT ► INSERT MOLDING ► PLASTIC FORMS AROUND INSERT ► NURELED AROUND DIAMETER FOR SLIPPING

9. MACHINE SCREWS WITH A THREADED METAL INSERT ► ADVANTAGES  FEWER PARTS REQUIRED FOR ASSEMBLY  INSERTS INTRODUCED DURING OR AFTER MOLDING  GOOD OVERALL DURABILITY  REPEATED ASSEMBLY

10. PLASTIC MACHINE SCREWS ► IDEAL CHEMICAL RESISTANCE APPLICATIONS ► MATERIALS:  Nylon  Acetal  Polypro  polyimide ► AVALIABLE IN STANDARD MACHINE THREADS

11. SELF THREADING SCREWS ► FEWER PARTS REQUIRED ► THREADS FORMED DURING ASSEMBLY ► MIN. FASTENER AND EQUIP. COST ► LIMITED DURABILITY ► REPEATED ASSEMBLY LIMITED

12. SELF THREADING SCREWS ► ELIMINATES METAL NUT MEMBER ► RECEIVING THREADS

13. SELF THREADING TERMS ► DESTRUCTION TORQUE:  torque required to cause failure ► SEATING TORQUE:  torque needed to attain the desired clamp loads ► STRIP TORQUE:  torque that would cause the nut threads to fail

14. SELF TAPPING SCREWS ► CUT OR TAP THEIR OWN THREADS ► SLASHED CUTTING SLOT

15. THREAD FORMING SCREWS ► NO CUTTING CAPABILITIES ► DISPLACE MATERIAL

16. SCREW FASTENERS ► ADVANTAGES  HIGHER PULL OUT FORCE  DISASSEMBLY IS EASIER  CAN BE REASSEMBLED EASILY

17. SCREW FASTENERS ► DISADVANTAGES  HAS GREAT IMPACT ON RECYCLING  EASILY REMOVED FOR RECYCLING

18. SPEACIAL THREAD FORMING AND THREAD CUTTING SCREWS

19. PLASTITE SCREW ► NON CIRCULAR TRILOBAL CROSS SECTION ► DESIGN REDUCES DRIVING TORQUE ► IDEAL FOR VIBRATION APPLICATIONS ► COLD FLOW LOCKS SCREW INTO PLACE

20. PLASTITE SCREW

21. PT SCREW ► WIDE SPACED SINGLE LEAD THREAD ► 30 DEGREE ANGLE OF FLIGHTS ► REDUCED RADIAL AND HOOP STRESS ► MODIFIED SHANK

22. PT-SCREWS

23. POLY FAST SCREW ► 35 DEGREE LEADING EDGE ► 10 DEGREE TRAILING EDGE ► SUITABLE FOR USE WITH MORE DUCTILE PLASTICS

24. HiLo SCREW ► DOUBLE LEAD SCREW ► THREAD FORMING AND THREAD CUTTING ► HIGH THREAD (30 DEGREE ANGLE) ► LOW THREAD (60 DEGREE ANGLE) ► DRIVE TORQUES ARE LOW ► 30 DEGREE ANGLE  REDUCES RADIAL PRESSURES  REDUCES TENDANCY FOR BOSS CRACKING

25. CONCLUSION ► CONNECTING MATING PARTS ► RECYCLING CONSIDERATIONS ► DESIGN CONSIDERATIONS  VIBRATION  PULLOUT FORCE  DEFLECTION

26. THE END