The vertical slide in the latch linkage of an exit device is coupled for vertical movement together with a channel inside the door stile. The channel holds a pair of blocks having inclined surfaces held in touching relation and relatively slideable. The vertical latch-operating rod is attached to the first of the blocks and the other block is secured to the channel by a horizontally disposed threaded adjusting element. The side walls of the channel restrict the first of the blocks from lateral but not vertical movement. The other block is restricted from lateral movement only by the threaded element, and turning the threaded element moves that block from side to side in the channel to raise or lower the first block as the inclined surfaces slide. This changes the effective length of the rod. The turning of the threaded element may be done from the outside of the door through an access hole.