New chuck ???
Had you used it all day every day? Didn't think so.
Stop arguing. He wore it out. No warranty covers wearing it out. No SDS will last if you use it for chiseling all day. It's cost him less than £2 per week. Stop whining.
No SDS drill will operate 24/7 chiseling concrete. It's just not possible to make such an instrument unless we find a new type of metal for the chuck mechanism.
You have to be fair to the manufacturer. It's cost him less than £2 per week and it's been worn out. A lifetime guarantee doesn't mean it's guaranteed for you life you know. Fair usage. He's worn it out. It's not a manufacturing fault.
No SDS drill will operate 24/7 chiseling concrete.
Ahh, so you think because of his gripe,