Worn thread on window lock

[northj]

The locks on my house windows operate by inserting and turning an allen key to tighten the handles so that they cannot turn.

One of the locks has become worn, whereby the allen key just turns in the lock without actually gripping the sides and allowing the window to be locked/unlocked.

At the moment I cannot open the window. I'm not too worried about being able to lock it again.

Any ideas/advice on how I can get the lock turning?

 

[masona]

An old screwdriver tightly into the hole as it got a wedge shape,might have to file the screwdriver tip end to approx the right size.