1. Welcome to the New & Improved BladeForums. New software info here. Please report problems in Tech Support, and read existing threads before posting! - Spark
  2. I've changed the default forum style to Flat Awesome based on feedback. Don't like it? Click here to change how the forums look Feedback on this is welcome here.

Why have a glass breaker on a knife?

Discussion in 'General Knife Discussion' started by DRider, May 12, 2008.

  1. DRider


    Jan 8, 2005
    Seems to me, if you are not in a professional capacity having to break windows fairly often (like someone in the military or someone who responds to car accidents) then in the rare emergency, you could just stab your knife into the window. Wouldn't the fact that your knife has a little sharp tip made of hardened steel work just as well as a glassbreaker?
  2. Bear Claw Chris Lappe

    Bear Claw Chris Lappe Gold Member Gold Member

    Apr 20, 2001
    No, it will more often than not break the tip of your blade.

    Glass breakers are thick for a reason.
  3. johnu2


    Jun 5, 2007
    Plus glass is normally hardened and can be quite tough to break (it's not as easy as you see in movies), couple that with the smooth (therefore slippery) surface of glass and it means that it's quite easy to slip and hurt yourself if you use the blade
    Last edited: May 12, 2008
  4. TheWayOfTheGun1


    Mar 9, 2007
    Better to have it and not need it... than need it and not have it ;-)
  5. longbeachguy


    Oct 11, 2005
    Never mind...............................
  6. DRider


    Jan 8, 2005
    Thanks, I appreciate the info. (you guys are fast, too)
  7. bobby.t


    Jan 24, 2007
    You'd be better off leaving the knife closed and just hitting the glass with the handle or flipper.
  8. dtownknifekid


    Dec 21, 2006
    I think a glass breaker is a great feature in case of an emergency. Like say you get into an accident or you arrive at a nasty one before the Paramedics and the victim is in immediate danger. There is also the fact that if something is designed for a job it will almost always do that job better than something designed for something else and then there is the fact that there is very little chance of injuring yourself with the glass breaker.
  9. Zero_Time


    Dec 28, 2006
  10. These_Nutz

    These_Nutz Banned BANNED

    May 2, 2008
    Using a point would be far better and even if you did break the tip if the situation calls for it then who cares if it saves your life.
  11. johnu2


    Jun 5, 2007
    The lock would fail before the tip broke in my opinion
  12. Khalnath


    Jun 12, 2005
    Agreed. Remember that glass is HARD! In an emergency I might try this with a sturdy fixed blade with a thick point, like my (Camillus made) Recon Tanto, but I wouldn't try it with a folder. I like having fingers.
  13. topspeclt


    Oct 30, 2006
    I think having a glass breaker is a fantastic idea and adds an additional use to folding knives other than cutting.

    There have documented rescue cases where people have tried to poke the knife point into the window to break it. In these cases, the point, pivot, blade break, hand slips or the blade slips because the force is not at a perfect right angle. It will probably totally impractical and dangerous to do such a thing with a knife.

    A small glass breaker on the otherhand can tackle most automobile windows (laminated or not) and create the cracks and the opening you need to open the window.

    If you keep a knife in the car its a great idea to have a knife with a cutting hook (for seat belts) and a glass breaker. So for rescue purposes such a feature is a life saver.

    Thanks to all those manufacturers that decided to include such a feature.
  14. Steven Andrews

    Steven Andrews

    Apr 7, 2002

    Tried it? It's called toughened glass for a reason.
  15. Blop


    Mar 7, 2003
    As long as they work. Are there any forum tests about it?
  16. tom19176


    Dec 7, 2005
    just do what 90% of the car theives I arrested in the past did, use a spark plug to break the glass. Works everytime in seconds.....
  17. mete

    mete Gold Member Gold Member

    Jun 10, 2003
    We've discussed this on the forum before.I have the best Benchmade seatbelt cutter and a automatic center punch to break the glass [always use the corner of the side windows]
  18. Rich357


    May 7, 2003
    Do the tie a string to the spark plug and swing it at the glass?
  19. DutchV


    Mar 4, 2007
    These guys have an answer, if you're carrying a MagLite or a steel baton:


    Check out the videos. It's not easy to break a car window.
  20. shecky


    May 3, 2006
    Depends on which kind of glass. Tempered stuff can be made to shatter pretty easily. Typical windshield glass is specifically made not to shatter, and can be really tough to break through. There's a neat Victorinox Rescue Tool video showing the difference between a windshield and a side window on a car.

    Yes. Do a youtube search, you'll find several videos of folks breaking glass easily with a spark plug insulator. Specifically, the porcelain, much harder than glass. Tempered glass acts like it's under tension, very tough, but once breached, the whole thing disintegrates.

    Knife based glass breakers seem to be a small, pointed piece of hardened metal. Probably harder than the typical knife blade.

Share This Page