Drill-bit definitions

1. Axis

2. Shank - straight, cylindrical

3. Drill body

4. Overall length L

5. Flute length l (helix)

6. Flute

7. Front flank surface

8. Front flank surface width

9. Core

10. Core thickness

11. Margin

12. Margin width

13. Secondary lip

14. Relief

15. Relief depth

16. Heel

17. Flank

18. Face

19. Lip

20. Cutting edge

21. Outer point

22. Cross cutting edge

23. Cross cutting edge length

24. Lip length

25. Drill diameter

26. Relief diameter

27. Back taper ratio

28. Lead of helix

29. Angle of twist (λ)

30. Cross cutting edge angle (ψ)

31. Nose angle (ε)

32. Lip angle (α)