I bought the welder new, and have put 700 hours on it in that time. I believe he said it did wear grooves, I am getting this info third party from the dealer I bought it from. The repair tech they sent it to is in Enid, Oklahoma. But I noticed the end bearing was spinning where it mounts in the bracket, the race was spinning so I told the dealer about it when I returned it. Miller has been good about standing behind the machine. It just gets frustrating spending tht kind of money on a machine and getting a lemon. hopefully this will be the end of my troubles.