tighten the screw(s) (on one)
To exert excessive and coercive pressure, force, or threats of violence on one. The bank has really started tightening the screws on me ever since I began missing my mortgage payments. I'll send one of my strong men around to him tomorrow to tighten the screw. Then we'll see if little Johnny's still so sure he won't sign the contract.
tighten (or turn) the screw (or screws)
exert strong pressure on someone. informal