Heavy metal pierce nut

1. A self-attaching fastener, comprising:

a central pilot portion having an outer side wall being annular;

an annular flange surrounding the central pilot portion, said annular flange having a planar end face defining a peripheral edge with a diameter greater than a diameter of said outer side wall of said central pilot portion;

said planar end face including a plurality of circumferentially spaced first anti-rotation elements, each of said first anti-rotation elements having a planar top face spaced above said planar end face of said annular flange, said planar end face further including a plurality of circumferentially spaced second anti-rotation elements, each of said second anti-rotation elements having a planar top face spaced below said planar end face of said annular flange, one of said plurality of first anti-rotation elements and said plurality of second anti-rotation elements radially extending from said peripheral edge of said annular flange to a location spaced from said outer side wall of said central pilot portion, the other of said plurality of first anti-rotation elements and said plurality of second anti-rotation elements radially extending from said outer side wall of said central pilot portion to a location spaced from said peripheral edge of said annular flange,

said first anti-rotation elements circumferentially alternating with said second anti-rotation elements.

2. The fastener set forth in claim 1 , wherein said first anti-rotation elements extend radially inwardly toward said central pilot portion from said peripheral edge of said planar end face.

3. The fastener set froth in claim 1 , wherein each of said top faces of said first anti-rotation elements and said second anti-rotation elements is inclined relative to said planar end face of said annular flange.

4. The fastener set forth in claim 1 , wherein said first anti-rotation elements define a trapezoidal cross-section.

5. The fastener set forth in claim 1 , wherein said annular flange defines an outer radial flange wall and said first anti-rotation elements define an outer radial element wall having a common plane with said outer radial flange wall.

6. The fastener set forth in claim 5 , wherein said outer radial flange wall defines a polygonal shape comprising a plurality of abutting planar surfaces.

7. The fastener set forth in claim 6 , wherein each of said first anti-rotation elements is aligned generally centrally with one of said planar surfaces.

8. The fastener set forth in claim 1 , wherein said second anti-rotation elements extend radially outwardly from a base of said central pilot portion.

9. The fastener set forth in claim 1 , wherein said central pilot portion defines an undercut and said second anti-rotation elements extend radially outwardly from beneath said undercut upwardly to a location spaced from said edge of said annular flange.

10. The fastener set forth in claim 1 , wherein said pilot portion defines a top face and an inclined outer wall, said inclined outer wall being spaced from said top face.

11. The fastener set forth in claim 1 , wherein said pilot portion defines a top face and an inclined outer wall spaced from said top face by a generally cylindrical wall.

12. The fastener set forth in claim 1 , wherein said planar top faces have an incline ratio of between about 1.7 and 1.1.

13. The fastener set forth in claim 1 , wherein said planar top faces have an incline ratio of about 1.3.

14. A self-attaching fastener, comprising:

a central pilot portion having an outer side wall being annular;

an annular flange surrounding the central pilot portion, said annular flange having a planar end face defining a peripheral edge with a diameter greater than a diameter of said outer side wall of said central pilot portion;

said planar end face including a plurality of circumferentially spaced first anti-rotation elements, each of said first anti-rotation elements having a planar top face spaced above said planar end face of said annular flange, said planar end face further including a plurality of circumferentially spaced second anti-rotation elements, each of said second anti-rotation elements having a planar top face spaced below said planar end face of said annular flange, one of said plurality of first anti-rotation elements said plurality of second anti-rotation elements radially extending from said peripheral edge of said annular flange to a location spaced from said outer side wall of said central pilot portion, the other of said plurality of first anti-rotation elements and said plurality of second anti-rotation elements radially extending from said outer side wall of said central pilot portion to a location spaced from said peripheral edge of said annular flange,

said first anti-rotation elements circumferentially alternating with said second anti-rotation elements,

said planar top faces having an angular incline ratio of between about 1.7 and 1.1.

15. The fastener set forth in claim 14 , wherein said planar top faces have an incline ratio of about 1.3.

16. The fastener set forth in claim 14 , wherein said first anti-rotation elements extend radially inwardly toward said central pilot portion from said peripheral edge of said planar end face.

17. The fastener set forth in claim 14 , wherein each of said top faces of said first anti-rotation elements and said second anti-rotation elements is inclined relative to said planar end face of said annular flange.

18. The fastener set forth in claim 14 , wherein said first anti-rotation elements define a trapezoidal cross-section.

19. The fastener set forth in claim 14 , wherein said annular flange defines an outer radial flange wall and said first anti-rotation elements define an outer radial element wall having a common plane with said outer radial flange wall.