This is for anyone that has experience with these clamps on Eagnas machines. How many racquets were you able to string before these wore out? Are they really diamond dusted as claimed? I have some on a Combo 710 dropweight, but after around 150 string jobs, I am having a lot of problems with clamp slippage. I have cleaned them twice. I am trying to determine if maybe my cleaning method is just not sufficent enough or if they eventually just wear out. I use a shoelace dipped in alcohol.