Review on 🔩 SST Identibolt: Your Ultimate Bolt and Nut Identifier Gauge by Kenneth Barnes

Many metric and standard screws (and nuts) are very similar, and of course this tool is there for the sole purpose of figuring out which is which. But even the tool can get tricky: In the first photo you can see a metric M6 (6mm) screw threaded into a "1/4-28 FINE" hole, which is a standard (non-metric) size . It seems to fit pretty well, but the trick is that you have to thread it ALL through to make sure it actually fits. In the second photo you can see that the bolt goes *almost* through the back, but not all the way. At this point it stopped spinning slightly, showing that it was in an incorrectly sized hole. (It goes through the corresponding M6 hole quite well). The maker of the instrument has wisely made it deep enough to be able to properly distinguish sizes in this way. The same applies to teaching mothers; Make sure they screw on easily before deciding you've found the right size. If your nut or bolt is rusted, this becomes more difficult. In this case, a thorough cleaning with a wire brush followed by a small amount of oil is helpful, although oxidation can distort the threads enough to make it difficult to thread the bolt through the threads in the tool. Help the bolt in. Obviously, if you strip the threads with a tool on a "stubborn" screw, you're just ruining an expensive gauge tool. So don't even think about picking up a wrench next to this thing. If it doesn't rotate under your fingers, it's the wrong size. If the screw doesn't seem to fit anywhere, then something else is wrong. It's probably just too rusty. Instead, find another screw to try, or buy the two metric sizes that are closest to yours plus the two standard sizes that are closest to yours and find out by actually trying them try it on your equipment. It's a lot cheaper than replacing this tool. Another possibility is if you're dealing with something really old, like 1948 or earlier, before "standard" threads were adapted to their current sizes and pitches. In this case, all bets are void and you will likely need to drill and rivet those holes to complete the repair. I have found this tool very helpful in sizing and then ordering the correct bolts to replace rusted and missing parts on my jeep and I think the time saving is worth the price!