A heat sink includes a first fin and a second fin. The spacing between the first fin and the second fin may be adjusted by a threaded rod. The threaded rod includes a first portion that is engaged with the first fin and a second portion that is engaged with the second fin. The thread pitch of the first portion and the second portion may differ. For example, the pitch of a first internal thread of the first fin may be smaller than the pitch of a second internal thread of the second fin. 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.