Forged a set of tongs last winter that taught me the same lesson the hard way. I kept fighting the steel, whacking it like it owed me money, and the jaws came out twisted and uneven. My buddy watched me for ten minutes, then told me to slow my swing down and just let the hammer do the work. Once I stopped muscling it, the metal moved where I wanted and the tongs actually lined up. Funny how we blame the anvil when the real problem is our own impatience at the forge.

Is it really that deep though?

A quarter turn. On one bolt. That is wild to me. The fact that a tiny bit of movement makes a tool walk 0.004 and ruins the cut is what gets me, because you would never guess it looking at the machine. You did everything right by the sound of it, checking program and offsets first, and the whole time it was a bolt you could have checked with one hand in half a minute. Fourteen scrapped parts plus two hours of staring at a screen that was fine is the part that hurts the most. I'm going to go check every clamp bolt on my mill tomorrow before the first run.