Hello my dear readers! Today we’ll also be skipping the usual car review and instead talking about fasteners. Scintillating stuff, I know. In all seriousness, for the past two weeks I’ve been repairing my car and I felt like imparting some of the wisdom I’ve picked up over the years. As some of you may know (or not) there are two main types of fastener sizes: SAE, or customary and metric. SAE, which stands for the Society of Automotive Engineers, are fastener sizes based on imperial measurements, typically even fractions of an inch. These sorts of fasteners are usually found on older American cars and occasionally on foreign vehicles if they’ve been the victims of a bit of “presidential engineering” (the practice of making something SAE fit where it really shouldn’t). Metric fasteners are based on millimeters, with typical sizes being M6, M8, M10 and so on. Foreign cars typically use metric fasteners and you can quickly tell what sort of car someone owns by seeing whether they have more metric or SAE wrenches.  These days, however, it’s not too odd to find metric bolts, screws and nuts in new American cars. With increasing globalization it makes sense that automakers won’t bother putting SAE fasteners on cars bound for America and metric ones on those bound for Australia, or Europe. 

Naturally, there exists some overlap between metric and SAE sizes. For instance, a 5/16 socket will fit on an 8mm bolt, but I wouldn’t recommend it. If you use a socket that’s just barely off enough times you risk damaging the bolt head and rounding it and then you’re in for some real trouble removing a stuck bolt. Remember: stay safe, stay legal and mind your fasteners.