1. home
  2. preface
  3. razor parts
  4. blade points
  5. razor identification
  6. the edge
  7. grinds
  8. grinds, why
  9. sharpening introduction
  10. stones
  11. strops
  12. using stones, introduction
  13. blade - stone geometry
  14. first stroke on stone
  15. last stroke on stone
  16. using the strop, introduction
  17. first stroke on strop
  18. last stroke on strop
  19. preparation for shave
  20. numbered shaving paths
  21. face, right side
  22. face, left side
  23. chin
  24. coup de maitre
  25. throat
  26. second over
  27. preface to archives
  28. La pogonotomia I
  29. La pogonotomia II
  30. La pogonotomia III
  31. La pogonotomia IV
  32. the razor I
  33. the razor II
  34. the razor III
  35. the razor IV
  36. the razor V
  37. the razor VI
  38. references
  39. summary
  40. guestbook

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The edge

sharp & dull


dullshrp.gif

Sharpness and dullness are defined as the edge sides meeting at a single point and a surface, respectively. This scheme shows a sharp and a dull blade.

strength

An edge should not chip off during adequate usage. Thin, weak and small-angled edges can handle delicate objects. The razor's 15-20* edge is an ideal compromise between sharpness and strength.

serrations

Under the microscope, even a perfect edge looks serrated. A perfect smooth edge would be ideal because it would split the molecular bonding of the object. Serrations act like a saw. The purpose of razor sharpening is to create a smooth edge, and to take advantage of the inevitable serrations as much as possible.

burr

burr.gif

Sharpening approaches the sides of an edge, forming a ragged, rough edge which is so weak that it bends away from the sharpening medium, as the scheme shows. This so called burr feels sharp first, but it is thin and weak and willl break away soon, exposing a dull surface. The burr is the signal that the two edge sides have joined. It can be a help when a lot of metal must be removed in wedge shaped blades; the second step is to remove the burr by honing at a greater angle. However, relying on a burr to save effort is not necessary in the hollow grind razors. The sharpening of razors differs from sharpening knives in that burr formation should be avoided.

It is difficult to measure and standardize sharpness. Electron microsocopic studies (Lee) showed that with a #6000 waterstone and subsequent honing with chromium oxide, can make a chisel sharper than a Wilkinson Sword razor blade.