I managed to break a very similar record vice at school.
Step 1. Admire the cross hatch mrakings on the vice jaws, think wouldn't that look nice on the copper plate I am making into a candle stick holder.
Step 2. Put said copper plate in vice and do up as hard as a 16 year old boy can.
Step 3. Take out said copper plate look at it very disapointedly at the lack of cross hatch pattern (a good vice shouldn't mark the workpiece).
Step 4. Come to obviouse logical conclusion, put copper back in vice and with the help of a 4 foot length of scaffolding tube wind vice up considerably more.
Step 5. Keep winding vice up until the inevitable very load bang when half a vice lands between your feet.
Step 6. Find this incredible ammuzing not helped by the teacher ranting about never knowing of any student managing to break one of those vices in 40 years of teaching.
Step 7. Make candle holder out of piece of copper with a really nice cross hatch pattern on it and present to Mum with a bill for a £100 vice.