Experiment to see the difference between healthy blade and weary one in sisters
These two blades, A and B, are constructed with kobuse style. They are half-sisters, since the core steel is different, while the outer steel is the same. Actually the outer steel is layered with two kind of steels those are outer steel and jacket steel on it.
Core steel = 12 time foldings, it is a little softer than the outer one.
Outer steel = 14 time foldings, it is hard and dense enough to become a sharp edge by proper tempering.
Jacket steel = 8 time foldings, it may have rough layer, because of less foldings.
Image of the steel construction of these blades. The upper side becomes an edge, and the bottom is a back.
Just after the quenching work
A
Blade length 75.8cm, thickness at the base8.3 mm, width 3.3cm, thickness at yokote 5.7mm, width 2.6cm, weight 1050g
B
Blade length 71.8cm, thickness at the base 8.2mm, width 3.3cm, thickness at yokote 6mm, width 2.6mm, weight 980g
Polished out
A
Blade length 75.7cm, thickness at the base 8mm, width 3.3cm, thickness at yokote 5.5mm, width 2.5cm, weight of naked blade 912g
B. It is ground out so much. Probably, the jacket steel is ground off in some parts.
Blade length 71.8cm, thickness at the base 7.6mm, width 3.0cm, thickness at yokote 3.8mm, width 2.1cm, weight 710g
Other examples to consider the inner effect of hardening work => An experiment to see the inner effect of hardening => Atanto blade of worn out