Can you please explain to me how to interpret (read) the reflections on the goneometer in relation to your published photos?
Thank you
Hi van,
in general - outer points are grinded edge reflections, inner points/lines/arc are blade profile reflections.
You can easily read grinded edge (outer) reflections, they look like points and show grinded angle. The reason why there are nearly point reflections is small edge thickness (ca 0,8 - 1,0 mm) and polished edge (SJ wheel + PA-77/FlexCut/Chromox). On thicker edges the points stretch, non-polished edge produces blurry reflections.
1st knife: 40° (20 + 20)
2nd knife: ca 35° (17,5 + 17,5)
3rd knife: ca 35° (17,5 + 17,5)
Reading inner reflections is not so easy due different blade surfaces, grind profiles and thicknesses. Furthermore, the laser beam is relatively narrow and does not have to cover the entire blade, so I am very careful with interpretation of inner reflections...
1st knife: Knife: ANV P200
Grind profile: High flat
Grind surface: Satin
Showed blade bevel angle: 5° + 5° with blurred trace to ca 7,5° + 7,5° due satin surface
2nd knife: Knife: Custom hunting knife
Grind profile: Hollow
Grind surface: Polished
Showed blade bevel angle: ca 7° + 7,5°, slightly uneven grind is visible
3rd knife: Knife: Custom hunting knife
Grind profile: High flat
Grind surface: Polished
Showed blade bevel angle: ca 5° + 5°
jvh