A Dowel Screw has threads on both ends and a square section in the middle that lacks threads. You would use a dowel screw to fasten two objects together and is typically used with wood and in the making of furniture. To insert the dowel rod you must first drill a hole that is slightly smaller than the dimensions of the dowel screw and a bit shorter than the length. After the hole is drilled you could use pliers to tighten the screw in place by gripping the dowel screw in the middle where there are not any threads. You could connect the other material onto the exposed end of the dowel rod by twisting in into place. Dowel screw make for a strong connection between two softer materials.