Effectiveness of a knife breaking glass? Emergency preparedness?

[Knivesinedc]

Hey everybody. I was browsing some YouTube videos the other day when i came across some "what would you do" type videos. The premise was to see what people would do when they thought there was a baby/toddler in a car alone on a hot day. The maker of the video set up a fake baby and sound effects inside of his car and left it in a parking lot with the crying sounds playing. One guy tried to break the window with his skateboard by hitting it several times, only to see the guy making the video run out and stop him before he did any real damage and let him know what was going on. And it got me thinking. What would i do if i was presented with that situation or a situation similar (I.E car crash). I know for sure I would get the child out at any means possible simply because you dot know what the circumstances are. How long has the child been in there? How long does He/She have left before the heat gets to them? but how? How could i get the child/person out of the vehicle quickly, and effectively as to minimize the potential of harm or death. I always have my knife on me, but is it sufficient to break a window? Could my linerless Military do it? or would my linered Manix2 do a better job? Would you simply smash the window out with the butt of the handle? Would it be worth it to carry something such as an Assist in addition to your normal EDC in the chance that a situation could arise that would require such a tool? What is the best possible option in this situation? Any thoughts and comments are appreciated. -Jake-

P.S I understand that its not always the best idea to pull someone who's just been in a crash out of their vehicle, because of the possibility of spinal and other serious injuries, that could be exasperated by moving them too much.

[The Deacon]

Knives, per se, do not make effective glass breakers. The only Spyderco I'd use to break glass would be the Assist, but that's because it has a dedicated glass breaker built into the handle. I own one, and keep it in my vehicle, and often carry a MT OTF that has a glass breaker/skull crusher. However, a spring loaded center punch would be cheaper and more effective if you don't already own an Assist.

[Blerv]

You have a better chance of glancing stab that results in the knife hitting you instead .

Carbide tips are available on knives and off them. I have one on my umbrella. Bust-A-Cap and XCapeCap makes a variety of glass breaking bezels for Streamlight, Surefire and Maglite flashlights.

[DRKBC]

I think it is a good idea. I keep a Benchmade Houdini tool in My wife's truck and mine as well, it has a glass breaker as well as hook for cutting through seat belt material and a LED light. I don't know if we will ever need it to save ourselves or someone else but for the 40 bucks it cost I think it is a worthwhile investment. So far my daughter has used it to cut tags off her purchases at the mall.

https://youtu.be/9b_FGQxNJbY

[Larry_Mott]

I (and my wife) carry this little fella, superior to any knife and not too big to carry with your car key.
https://youtu.be/z1J30v89gtY

[jmh58]

I (and my wife) carry this little fella, superior to any knife and not too big to carry with your car key.
https://youtu.be/z1J30v89gtY

Thanks Larry.. Have to get a few!!! John :)

[Larry_Mott]

I (and my wife) carry this little fella, superior to any knife and not too big to carry with your car key.
https://youtu.be/z1J30v89gtY

Thanks Larry.. Have to get a few!!! John :)

Good man! They're dirt cheap too, compared to even the most crap knife :)

[demoncase]

Two points:
1. I normally (being an office berk) carry a tactical pen with a glass breaker point in my top pocket as I travel for precisely this purpose.....I've accidentally hit the point of knives on toughened glass before- only to have it skid away or toward me with the same amount of force that I applied to it. Worrying!

2. Anyone with aftermarket tinting might want to consider that these films make it nearly impossible to break a car window and have it fall away- the flim retains all the pieces and makes it very, very hard to smash out.

[jmh58]

Any time you are breaking an auto side glass, the point of impact should be as close to an edge as you can get..

Aftermarket tinted glass will break with no problem if ya get to the edge.. Just broke one last week with no problem.. Had an old window I needed to get rid of and this was an experiment.. And the tint held most of the glass pieces too.. Used the spring loaded center punch to do this that Deacon suggested.... John

[Monocrom]

Yup, best to get a dedicated glass breaker.

[Donut]

Most of the dPX Gear knives are being produced with a carbide tip glass breaker. That and the bottle opener :p give me a little peace of mind when traveling on the weekends or I'm out and about.

I do have a ZT pen with a carbide tip on the end, but rarely carry it.


I do sort of feel like there is as much chance that you will need to get through glass when you are away from your car.

I also have an Assist in my car.

[RexGig0]

The one knife I carry everywhere, every day, is an Assist. It does not "rotate" with anything else.

[Evil D]

Auto glass is some interesting stuff. In many cases it's extremely strong for what it is, but in other situations it's extremely easy to break. You just need to know a few tricks and know the weaknesses to get it broke easily. The first problem is most people automatically hit a window right in the middle, which is probably the strongest point. The secret is in the corners/edges.

https://youtu.be/iR5LlsdtV6E

I've even heard of people using their seat belt buckle to break windows. I would probably reach for my multi tool and use the plier tip in the corner.

[Michael Janich]

A few years back when I was working for BlackHawk, I designed a knife called the HawkHook. Masters of Defense had a number of knives with fixed carbide glass breakers, but they were very expensive and the fixed breakers were a hazard to your hand every time you reached into your knife pocket. I was curious about the ability of standard blade steel to break car windows and liked the idea of the hammer-style glass-breaking tools you often see in buses and trains because they deliver more power and are safer. My thought was to combine the ballistic power of a hammer-style strike with an inexpensive, pocket-sized tool that could be made with ordinary materials.

To test the concept, I made a non-folding prototype out of O-1, heat treated it with a propane torch, and cut a deal with the local auto salvage yard to break some windows for a flat fee. The concept worked, so I designed the folding version that became the HawkHook. Its glass breaker is nothing more than a pyramid shaped point on the edge side of the AUS-8 blade. Open the blade, grip the handle with a pinch grip, swing and break. This video shows a number of breaks, starting at about 0:45: https://youtu.be/cJC15lEZwx0" onclick="window.open(this.href);return false;.

BTW, if you're curious as to why most of the windows are spidering but not falling completely away, it's because they are rear quarterpanel windows, not door windows. The guy in the bib overalls at the auto salvage place said I could break as many quarterpanel windows as I wanted because he didn't have the tools to pull them and sell them. Door windows, however, were $40 each. BlackHawk was cheap and my budget was limited (I shot and edited the video as a one-man show), so I did what I could with my $100 budget.

The HawkHook makes a great money clip and includes a flat-blade screwdriver, hook-style seat belt cutter (with a back-up serrated edge), and wire stripper, as well as a workable glass breaker that you can keep in your pocket at all times. Best of all, it's very affordable--at least as long as BlackHawk is still making knives. Who knows how long that will be...

Stay safe,

Mike

[David from NC]

Have never used a knife but have broke windows several times for felon removal and to gain entry...and in training. In a class last year we were "breaking and raking" with carbines. Even with M4s, it takes good technique and a lot of force. I failed to break one with three attempts using the muzzle, but the FOURTH time was a charm. As said you go to the corner or edge and hit sharply and firmly where it's most "supported". In two cases I used the bottom of a SIG P220...although I can't suggest that now (can't even believe I did it really but both were after chases with adrenaline and urgent need to get the BG out quickly and it was all I had in my hand.)

I know one deputy that hit a window that was open about 3" with his flashlight about 5 or 10 times and it didn't break (because of all the "give") I know guys that have wailed at glass with ASP batons with some good and some not so good results... I say all this to say that I don't know if I would relay on a simple knife attachment...or if I did I'd know not to expect it to shatter on the first time.

[Evil D]

Have never used a knife but have broke windows several times for felon removal and to gain entry...and in training. In a class last year we were "breaking and raking" with carbines. Even with M4s, it takes good technique and a lot of force. I failed to break one with three attempts using the muzzle, but the FOURTH time was a charm. As said you go to the corner or edge and hit sharply and firmly where it's most "supported". In two cases I used the bottom of a SIG P220...although I can't suggest that now (can't even believe I did it really but both were after chases with adrenaline and urgent need to get the BG out quickly and it was all I had in my hand.)

I know one deputy that hit a window that was open about 3" with his flashlight about 5 or 10 times and it didn't break (because of all the "give") I know guys that have wailed at glass with ASP batons with some good and some not so good results... I say all this to say that I don't know if I would relay on a simple knife attachment...or if I did I'd know not to expect it to shatter on the first time.

This is it in a nutshell. Auto glass is actually quite flexible. It has to be, because the chassis of a car is not 100% perfectly rigid, so it needs to flex a certain amount with the chassis (as does the sealant that holds the glass in). When you strike a window in the center, chances are good it's just going to flex and you're going to bounce off of it. When you hit it at the edge where it's sealed to the car, it doesn't have any give behind it, so you're much more likely to break it.

This video is a perfect example of just how flexible auto glass is. This is just the first video I found on a You Tube search, so I have no idea who this is, but I'm well aware of what bass can do to glass (and metal, and a lot of things but that's another subject). I've seen glass ripple like water before it breaks.

https://youtu.be/1QniZ6cVqF4

[Dr. Snubnose]

Knives, per se, do not make effective glass breakers. The only Spyderco I'd use to break glass would be the Assist, but that's because it has a dedicated glass breaker built into the handle. I own one, and keep it in my vehicle, and often carry a MT OTF that has a glass breaker/skull crusher. However, a spring loaded center punch would be cheaper and more effective if you don't already own an Assist.

Agreed....Deacon is right on spot...+1....Doc:)

[Evil D]

Well, this is very interesting. The only thing I wonder about is the age of the window he busted. I'm not sure if the techniques for making auto glass has changed since that car was made.

https://youtu.be/QhlmKHbPFhU
https://youtu.be/llu-ckEe5cQ

Seems we've been over complicating this subject all along. Just take some old spark plugs and bust them up, and store them in your glove box in a ziploc baggie and you're ready to go.


Here's how that works, according to National Geographic.

https://youtu.be/ArUnuEUd4VU

[TomAiello]

My father in law was a career firefighter, and he's given everyone in the (extended) family glass breakers for every vehicle (and seatbelt cutters, actually). They're cheap and light, and they just live between the front seats of all our vehicles.

[Dr. Snubnose]

My father in law was a career firefighter, and he's given everyone in the (extended) family glass breakers for every vehicle (and seatbelt cutters, actually). They're cheap and light, and they just live between the front seats of all our vehicles.

+1 Tom and Kudos to your Father In Law!!!...Doc:)