Basically I think having to rely on Stone Axes is somewhat silly when you can work steel.
Problem is that Stone Axe is simpliest to raise in quality and mass-produce.
My suggestion is that Tools gain derived attributes from quality instead using raw quality in formulas. Armor gains Deflect/Absorb and Hitpoints from quality. Similarily sharp tools can be
Stone Axe q10/q50
Chop: 10/50
Chip: 10/50
Skin: 10/25
Butcher: 10/25
Harvest 10/
Shear
For Skinning, Butchering and Shearing you could make metal tools that would gain higher score to be used in the formula than their quality.
Also tools should be separated from just "hard metal" to bronze, wrought iron and steel tools which all have better ratio for quality=sharpness score.
For example for shearing sheep: Stone Axe q100<Bronze Shears q30<Iron Shears q20<Steel Shears q10
I am really bad at formatting this. Try asking questions and I will try to explain my idea.