Let the sides of the triangle be \( x, y, z \), where their ratio is given as \( \frac{1}{2} : \frac{1}{3} : \frac{1}{4} \). The least common multiple of 2, 3, and 4 is 12. Thus, the sides are \( 6k, 4k, 3k \), where \( k \) is the common multiplier.
The perimeter is 52 cm, so:
\[
6k + 4k + 3k = 52
\]
\[
13k = 52
\]
\[
k = 4
\]
The smallest side is \( 3k = 3 \times 4 = 12 \, \text{cm} \).