I checked the math; over 99% of the smaller craft brewers I visit that have can lines do not use one of the most critical pieces of lab equipment to check seams: the seam stripper. To be fair, these locations have been taught to manually tear down the double seam using a pair of pliers, or the ubiquitous black handled can opener. Years ago, when the aluminum cans and lids were a heavier gauge, this manual tear down method worked ok. One could still reasonably measure the critical to quality internals: coverhook, bodyhook, tightness rating, and pressure ridge, with the overlap being calculated using a formula. However, these days the manual tear down leaves a lot to be desired; the cans are essentially mangled. I highly recommend making the investment for a seam stripper. They are available from any lab equipment provider that specializes in can seaming technology. They are essentially a drill press with a cutting head that cleanly strips the seam from the can, exposing a perfect tear down where proper inspection and measurements can be taken. The attached cross section explains how the cutting head works to separate the coverhook from the bodyhook. Your lab tech's and can line operators will be grateful! Happy Canning!