Self counter-sinking fastener

1. A self-countersinking fastener for engagement with wood or similar composite material, said fastener including a penetrating shaft and a tool engaging head; wherein said tool engaging head is substantially frusto-conical in overall shape and provided with one or more indent regions into which said material may be pushed as the head is turned; wherein each of said indent regions include:

a trench extending substantially vertically through the entirety of said head; and

a tailing section extending through the entire height of the head and extending forward in the direction of turning from said trench to the next said trench, or through at least 90°, such that the radius of the head in the corresponding section increases throughout said section.

2. The fastener of claim 1 , wherein there are two said trenches and corresponding tailing sections, arranged opposite one another in respect of said head.

3. The fastener of claim 1 , wherein there are three said trenches and corresponding tailing sections, arranged at substantially even intervals about said head.

4. The fastener of claim 1 , wherein there are four said trenches and corresponding tailing sections, arranged at substantially even intervals about said head.

5. The fastener of claim 1 , wherein said trench has a profile of a truncated ‘V’ that extends toward the centre of the fastener from the periphery of the tool-engaging head and from the periphery of said tailing section.

6. A self-countersinking fastener for engagement with wood or similar composite material, said fastener including a penetrating shaft and a tool engaging head; wherein said tool engaging head is substantially frusto-conical in overall shape and provided with one or more indent regions into which said material may be pushed as the head is turned; wherein each of said indent regions include:

a trench extending substantially vertically through the entirety of said head; and

a tailing section extending through the entire height of the head and extending forward in the direction of turning from said through at least 90°, such that the radius of the head in the corresponding section increases throughout said section.

7. The fastener of claim 6 , wherein there are two said trenches and corresponding tailing sections, arranged opposite one another in respect of said head.

8. The fastener of claim 6 , wherein there are three said trenches and corresponding tailing sections, arranged at substantially even intervals about said head.

9. The fastener of claim 6 , wherein there are four said trenches and corresponding tailing sections, arranged at substantially even intervals about said head.

10. The fastener of claim 6 , wherein said trench has a profile of a truncated ‘V’ that extends toward the centre of the fastener from the periphery of the tool-engaging head and from the periphery of said tailing section.

11. A self-countersinking fastener for engagement with wood or similar composite material, said fastener including a penetrating shaft and a tool engaging head; wherein said tool engaging head is substantially frusto-conical in overall shape and provided with one or more indent regions into which said material may be pushed as the head is turned; wherein each of said indent regions include:

a trench extending substantially vertically through the entirety of said head; and

a tailing section extending through the entire height of the head and extending forward in the direction of turning from said to the next said trench such that the radius of the head in the corresponding section increases throughout said section.

12. The fastener of claim 11 , wherein there are two said trenches and corresponding tailing sections, arranged opposite one another in respect of said head.

13. The fastener of claim 11 , wherein there are three said trenches and corresponding tailing sections, arranged at substantially even intervals about said head.

14. The fastener of claim 11 , wherein there are four said trenches and corresponding tailing sections, arranged at substantially even intervals about said head.

15. The fastener of claim 11 , wherein said trench has a profile of a truncated ‘V’ that extends toward the centre of the fastener from the periphery of the tool-engaging head and from the periphery of said tailing section.