Boy, have things changed! Do you remember the many generations of three-angle seat cutters and what we used to get by with? Grinding seats is still needed, but just 10 years ago we were grinding 80 percent of the seats. Though we still grind when necessary, today we cut 90 percent of the seats in the heads. In addition, we also need a good indicator for measuring valve seat runout after we cut the seats. Yes, we use a vacuum tester, but we still need to know what we are cutting for runout when machining seats.