CountryBoy19
Grandmaster
To be honest I don't know the name of the method, but it's a nifty little scope thing you use for NDI purposes on cracks, corrosion etc. You set the scope on the surface of the object to be NDI'ed, and adjust the focus ring until the surface comes into clear focus. Zero the guage, then adjust for focus at the bottom of the engraving, crack, gouge, rust pit etc, and read the measurement on the gauge. I can't recall for certain but I'm pretty sure it only reads to .001" and there is possibility of a small margin of error in the user's determination of "in focus". Either way, I'm confident that my engraving is at least .005" even accounting for a generous margin of error.
