#### Answer

The difference between the cutting-edge width of the two chisels with the narrowest blades is $\frac{1}{4}$.

#### Work Step by Step

The cutting-edge width of the two chisels with the narrowest blades are $\frac{1}{2}”$ and $\frac{1}{4}”$. The difference between them is computed by subtraction:
$\frac{1}{2} - \frac{1}{4} = \frac{2}{4} - \frac{1}{4} = \frac{2-1}{4} = \frac{1}{4}$.