Originally Posted By: CapriRacer
More detail on hammering on a deep socket to remove a rounded nut or bolt.
Choose the next size down - and that includes both metric and English. So the next size down from a 19 mm is 18 mm, but the next one down from 18 mm is 11/16".
Use a 12 point deep socket.
If that size slips, go down one more size.
Also, be sure you use PB Blaster on the threads. Patience is a virtue here. I've gone 2 or 3 days of soaking when I could spare the time.
Impact drivers are the best. Breaker bar, not as good.
That is exactly how we did it at the junk yard I worked at. It also usually worked for locking lug nuts we did not have a key for also. The 12 point sockets fit and grip the best.
Be sure to wear safety glasses. The socket could shatter, especially if it is not an impact socket.