This emergency multitool is a must-have auto accessory

Originally published at: This emergency multitool is a must-have auto accessory | Boing Boing

For many years until recently (when I removed it), my wife kept a hammer in her glove box in case her car went into a deep river or lake and she had to break the window to escape.

Never mind that the hammer was about 8 ounces in weight and couldn’t drive anything bigger than a tack let alone break a window, and the only body of water she drove near was the Susquehanna River, which is notoriously “a mile wide but a foot deep,” her dad told her to keep one, and she did. Bless her heart.


[quote=“alboalt, post:2, topic:193931”]
the Susquehanna River, which is notoriously “a mile wide but a foot deep,”
[/quote] is quite a bit deeper in some places, depending on the season.

This folk wisdom seems like a very loose peg on which to hang your (or anyone else’s) life. Secondarily, there are more reasons than being submerged in water to have a safety hammer in your car. A tack hammer is clearly a poor choice, but it’s a lot better than your current choice.

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At Interstate 83’s crossing of the river, the bridge is high and the riverbed is essentially rock, especially on the west side, so your car is crushed by the fall and the tack hammer is useless because you are deader than Elvis.

Edited to add: i drove my jon boat from the dock street dam to the York haven dam from ice out to Christmas for 20 years in search of smallmouth bass, so I know that the river stage varies and can identify the Harrisburg stage by sight

I guess you’re telling me that there is no reason to ever think you might need to break the glass to escape your car. Fair enough.


A small hammer likely won’t break automotive tempered glass. A big hammer likely won’t either unless someone takes a pretty big swing at it, which is hard to do from inside. Automotive tempered glass needs something harder and more concentrated than a treated-steel hammer-blow to induce the stress required to shatter. A small, pointed tungsten carbide or ceramic tool will do the trick with far less effort. The person you’re responding to is correct to say that a tack hammer is worse than useless in such an emergency situation.

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Breaking car windows is less about brute strength than it is about focusing an impact on a point. Tempered safety glass can be quite resilient when hit with a blunt object, but can easily shatter when hit with a sharp pointed object. Lightweight and small safety devices like the Life Hammer can work really well for their intended purpose.

There’s plenty of YouTube videos out there where you can observe an automotive window taking dozens of hits with a 1lb claw hammer without breaking, but immediately shattering with a single hit from a tiny cigarette lighter sized glass breaking device.


I thought I was alone in still keeping a pocket fisherman in the glove box.

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