Ten-millimeter sockets go missing a lot. I know this is a thing because I’ve worked in shops with shared toolboxes. I built Formula SAE race cars in college, and I have always spent a fair amount of time in fabrication shops as an engineer. These shared toolboxes are totally devoid of 10mm . I know this is a thing for other people too because I see about it. I also noticed Amazon sells packs of 10mm sockets in quantities .

The reason for this is straightforward: 10mm is one of the most common size fastener heads on modern vehicles, and thus one of the most commonly used tools. First to go always seems to be the deep ¼” drive 10mm socket. This is often followed by the standard ⅜” drive 10mm socket, then the 10mm wrench, and then the standard ¼” and deep ⅜” drive 10mm sockets, and finally the 10mm nut drivers. This order may change depending on which socket in the toolbox is easiest to reach. Thankfully, there are no imperial fractions that are close enough to 10mm, otherwise, those would disappear, too. But if the 7/16” sockets start disappearing, you have a serious problem.

About this time, someone will take a company credit card and drive to the nearest hardware store to buy a handful of 10mm tools and a couple of new Phillips #2 screwdrivers. Phillips #2 screwdrivers are the only thing that even comes close to disappearing as much as 10mm tools, and sometimes more often depending on the project.

A lot of tools will show back up after a project has been finished and everything gets cleaned up. But many tools, and often most of the 10mm, will never come back. Either they were taken, left inside the project vehicle, accidentally thrown away, or perhaps the have expanded their business.

I’ve owned many terrible cars, several of them made by Chrysler; so naturally, I own an increasingly large set of tools. My basic wrench and socket set is the same Craftsman set I’ve had for about 20 years, and it still has all the original 10mm sockets and wrenches that it came with. I’ve lost other tools; I once found a ⅝” wrench in the fender of my old Dodge Dart many years after I originally lost it. So now I have two of those, which is nice. At times, a 10mm socket has gone missing for a short time, but it always shows up under my tool pile, or on the floorboard of my car a few hours later.

How can this be? I use my tools all the time. I’m always building something, usually or somethings, and the 10mm is the most commonly used size. I want to say it is because I put my tools back when I am finished, but I don’t do that. I tend to leave my tools out as I use them until I either finish the project or my tool pile becomes too large to dig through. I’m actually pretty messy and nonchalant with tool organization outside the toolbox, which makes this all the more surprising.

No, I believe the reason that I have never lost a 10mm tool is that I, Matt Brown, am a wizard. I, somehow, have the ability to manifest 10mm tools at will, by merely uttering the incantation: “Where the hell is that damn thing.”

I think you will agree with me that this is the only logical conclusion.