toroidal distance to case

Be careful not to create an unintended 'turn' on the toroid through the mounting bolt and the metal enclosure.
It's my fear : I have only 1cm around
What would be the purpose of fitting a toroidal power transformer (I think a 50/60 Hz one) inside a tight , presumably SMPS PC supply?
reuse parts from dead apparatus : it make a correct enclosure for a linear power supply 😉