A heat sink includes a threaded rod. The threaded rod includes a first portion and a second portion. The first portion may engage with a first heat sink fin and a second portion may engage with a second heat sink fin. The first portion includes a first external thread of a first diameter. The second portion includes a second external thread also of the first diameter and of different pitch than the first external thread. For example, the pitch of a first knurl of the threaded rod may be smaller than the pitch of a second threaded knurl of the threaded rod. The spacing of the heat sink fins may be adjusted based upon the current operating conditions of the electronic device to maintain an optimal temperature of a heat generating device during device operation.