# Is there a name for that dynamite box thing? **URL:** \ **Category:** Factual Questions\ **Created:** [May 21, 2004, 2:49pm UTC](https://boards.straightdope.com/t/is-there-a-name-for-that-dynamite-box-thing/246363 "2004-05-21T14:49:38Z")\ **Posts on this page:** 18\ **Page:** 1
**Author:** ![Sat\_on\_Cookie](https://avatars.discourse-cdn.com/v4/letter/s/71c47a/32.png) [@Sat\_on\_Cookie](https://boards.straightdope.com/u/Sat_on_Cookie)\ **Post date:** [May 21, 2004, 2:49pm UTC](https://boards.straightdope.com/t/is-there-a-name-for-that-dynamite-box-thing/246363/1 "2004-05-21T14:49:38Z")
This is possibly the stupidest thread ever, but my brains have fallen out at the moment. Like, on cartoons when they push down on the lever that’s attached to a box and dynamite explodes? What would you call that? ---
**Author:** ![CandidGamera](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/candidgamera/32/2878_2.png) [@CandidGamera](https://boards.straightdope.com/u/CandidGamera)\ **Post date:** [May 21, 2004, 2:52pm UTC](https://boards.straightdope.com/t/is-there-a-name-for-that-dynamite-box-thing/246363/2 "2004-05-21T14:52:32Z")
I believe, if I recall correctly, it is a “plunger”. ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [May 21, 2004, 3:05pm UTC](https://boards.straightdope.com/t/is-there-a-name-for-that-dynamite-box-thing/246363/3 "2004-05-21T15:05:00Z")
I have a copy of **Explosives** sitting here on my desk, and have looked through it – I would’ve thought that it was called a _detonator_ or an _initiator_, but those terms have specific meanings. _Plunger_ isn’t listed. I always wondered how those things work, and I finally learned at the Museum of Natural History at the University of Utah – they have a mock-up of an Old West mine, with one of those detonating plungers. The side is cut away, so you can see the guts. Attached to that handle is a serrated-tooth pinion that meshes with a pinion/gear that’s attached to the shaft of a little generator. Pushing down on the handle briskly thus generates a voltage. At the bottom of the plunger shaft is an electrical contact that, when it gets to the bottom of its run becomes the thrown part of a switch completing a circuit with the generator. I couldn’t tell if there was anything more to it – if the direct AC output of the generator triggered the explosion (that would be my guess – keep it simple) or if it went through a rectifier and into a capacitor to store up a bit charge to be released by that switch. Nowadays, of course, all you need is a battery and a swich. Construction guys doing blasting probably just use a safety-switched unit with a battery and a switch. I know model rocket guys do. If I’m not mistaken, pyrotechnics experts in the movies use complex boxes that basically control timing of the release of current from batteries or wall voltage. ---
**Author:** ![Frank\_2](https://avatars.discourse-cdn.com/v4/letter/f/8c91f0/32.png) [@Frank\_2](https://boards.straightdope.com/u/Frank_2)\ **Post date:** [May 21, 2004, 3:06pm UTC](https://boards.straightdope.com/t/is-there-a-name-for-that-dynamite-box-thing/246363/4 "2004-05-21T15:06:04Z")
> [@CandidGamera](#): > > I believe, if I recall correctly, it is a “plunger”. This is what I’ve always heard it called. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [May 21, 2004, 3:11pm UTC](https://boards.straightdope.com/t/is-there-a-name-for-that-dynamite-box-thing/246363/5 "2004-05-21T15:11:25Z")
It is a [magneto blasting detonator](http://www.nwmangum.com/FunStuff/Detonator-1.html). When you push down the plunger, the rack gear on the plunger shaft turns a pinion gear on a magneto (a type of electrical generator) shaft. The current this produces sets off the primer charge, which in turn detonates the dynamite or whatever explosive you happen to be using. ---
**Author:** ![Sat\_on\_Cookie](https://avatars.discourse-cdn.com/v4/letter/s/71c47a/32.png) [@Sat\_on\_Cookie](https://boards.straightdope.com/u/Sat_on_Cookie)\ **Post date:** [May 21, 2004, 3:14pm UTC](https://boards.straightdope.com/t/is-there-a-name-for-that-dynamite-box-thing/246363/6 "2004-05-21T15:14:15Z")
WOW. Thank you.\* \*this is the best damn message board in the freakin’ world ---
**Author:** ![Sat\_on\_Cookie](https://avatars.discourse-cdn.com/v4/letter/s/71c47a/32.png) [@Sat\_on\_Cookie](https://boards.straightdope.com/u/Sat_on_Cookie)\ **Post date:** [May 21, 2004, 3:18pm UTC](https://boards.straightdope.com/t/is-there-a-name-for-that-dynamite-box-thing/246363/7 "2004-05-21T15:18:12Z")
> [@CalMeacham](#): > > I have a copy of **Explosives** sitting here on my desk P.S. **CalMeacham** , this just struck me as really funny. I’d ask to have it for a signature, but I think it would be in bad taste these days. ---
**Author:** ![Philster](https://avatars.discourse-cdn.com/v4/letter/p/13edae/32.png) [@Philster](https://boards.straightdope.com/u/Philster)\ **Post date:** [May 21, 2004, 3:29pm UTC](https://boards.straightdope.com/t/is-there-a-name-for-that-dynamite-box-thing/246363/8 "2004-05-21T15:29:27Z")
Does ACME have the patent on that? 😛 ---
**Author:** ![Master\_Wang-Ka](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/master_wang-ka/32/3325_2.png) [@Master\_Wang-Ka](https://boards.straightdope.com/u/Master_Wang-Ka)\ **Post date:** [May 21, 2004, 3:39pm UTC](https://boards.straightdope.com/t/is-there-a-name-for-that-dynamite-box-thing/246363/9 "2004-05-21T15:39:35Z")
Hm. “Bugs Bunny Style Magneto Blasting Detonator.” Could we have finally found a replacement for “1920s Style Death Ray?” ---
**Author:** ![Yllaria](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/yllaria/32/3452_2.png) [@Yllaria](https://boards.straightdope.com/u/Yllaria)\ **Post date:** [May 21, 2004, 3:49pm UTC](https://boards.straightdope.com/t/is-there-a-name-for-that-dynamite-box-thing/246363/10 "2004-05-21T15:49:59Z")
Gotta be: “ **1920s** Bugs Bunny Style Magneto Blasting Detonator.” ---
**Author:** ![Diceman](https://avatars.discourse-cdn.com/v4/letter/d/22d042/32.png) [@Diceman](https://boards.straightdope.com/u/Diceman)\ **Post date:** [May 21, 2004, 4:23pm UTC](https://boards.straightdope.com/t/is-there-a-name-for-that-dynamite-box-thing/246363/11 "2004-05-21T16:23:08Z")
Rest assured that this is definitely _NOT_ the stupidest thread ever. That dubious honor goes to “Someone told me that a duck’s quack doesn’t echo. Is this true?” or any variant thereof 🙂 ---
**Author:** ![Sat\_on\_Cookie](https://avatars.discourse-cdn.com/v4/letter/s/71c47a/32.png) [@Sat\_on\_Cookie](https://boards.straightdope.com/u/Sat_on_Cookie)\ **Post date:** [May 21, 2004, 4:47pm UTC](https://boards.straightdope.com/t/is-there-a-name-for-that-dynamite-box-thing/246363/12 "2004-05-21T16:47:56Z")
I can’t even believe I’m doing this, but I have to ask for clarification. **Q.E.D** , is the _specific_ box you referenced a magneto blasting detonator? i.e., if I was just going to reference it (yes, there is some rhyme or reason to this) would I simply say a blasting detonator or are the _all_ magneto b.d.s? ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [May 21, 2004, 4:57pm UTC](https://boards.straightdope.com/t/is-there-a-name-for-that-dynamite-box-thing/246363/13 "2004-05-21T16:57:59Z")
> [@Sat on Cookie](#): > > I can’t even believe I’m doing this, but I have to ask for clarification. **Q.E.D** , is the _specific_ box you referenced a magneto blasting detonator? i.e., if I was just going to reference it (yes, there is some rhyme or reason to this) would I simply say a blasting detonator or are the _all_ magneto b.d.s? Oh no, there are other types of blasting detonators. Some types use a piezoelectric element (similar to the type found in some pushbutton cigarette lighters), while others use a battery and a series of interlock switches to prevent accidental ignition. All of them have the common purpose of ensuring that the charge is absolutely safe until the device is triggered intentionally. ---
**Author:** ![Sat\_on\_Cookie](https://avatars.discourse-cdn.com/v4/letter/s/71c47a/32.png) [@Sat\_on\_Cookie](https://boards.straightdope.com/u/Sat_on_Cookie)\ **Post date:** [May 21, 2004, 5:08pm UTC](https://boards.straightdope.com/t/is-there-a-name-for-that-dynamite-box-thing/246363/14 "2004-05-21T17:08:49Z")
Thanks very much, **Q.E.D.**. I’m actually using the information in an article I’m writing, so you really helped me out. ---
**Author:** ![Padeye](https://avatars.discourse-cdn.com/v4/letter/p/a9a28c/32.png) [@Padeye](https://boards.straightdope.com/u/Padeye)\ **Post date:** [May 21, 2004, 6:20pm UTC](https://boards.straightdope.com/t/is-there-a-name-for-that-dynamite-box-thing/246363/15 "2004-05-21T18:20:26Z")
> [@Yllaria](#): > > Gotta be: “ **1920s** Bugs Bunny Style Magneto Blasting Detonator.” Unfortunately Bugs didn’t appear until _Porky’s Hare Hunt_ in 1938. He was a proto-bugs at that as Tex Avery’s version didn’t hit the screen until '40 in _A Wild Hare_. You could have a depression era, Bugs Bunny style mageto blasting generator I suppose. I’m sure plenty were used on WPA projects. ---
**Author:** ![BMalion](https://avatars.discourse-cdn.com/v4/letter/b/e274bd/32.png) [@BMalion](https://boards.straightdope.com/u/BMalion)\ **Post date:** [May 21, 2004, 6:44pm UTC](https://boards.straightdope.com/t/is-there-a-name-for-that-dynamite-box-thing/246363/16 "2004-05-21T18:44:37Z")
This thread _alone_ is worth $4.95! **Q.E.D.** , great link. ---
**Author:** ![matt](https://avatars.discourse-cdn.com/v4/letter/m/a6a055/32.png) [@matt](https://boards.straightdope.com/u/matt)\ **Post date:** [May 21, 2004, 7:25pm UTC](https://boards.straightdope.com/t/is-there-a-name-for-that-dynamite-box-thing/246363/17 "2004-05-21T19:25:49Z")
> [@CalMeacham](#): > > I couldn’t tell if there was anything more to it – if the direct AC output of the generator triggered the explosion (that would be my guess – keep it simple) or if it went through a rectifier and into a capacitor to store up a bit charge to be released by that switch. The older machines did not have capacitors. As you pushed the plunger down, the magneto was on open circuit and rotational K.E. was stored in the spinning armature, which acted as a flywheel. When the circuit was closed at the bottom of the stroke, the accumulated K.E. of the still-spinning armature was converted to a short-lived, high-power discharge. ---
**Author:** ![hermann](https://avatars.discourse-cdn.com/v4/letter/h/b487fb/32.png) [@hermann](https://boards.straightdope.com/u/hermann)\ **Post date:** [May 22, 2004, 3:50am UTC](https://boards.straightdope.com/t/is-there-a-name-for-that-dynamite-box-thing/246363/18 "2004-05-22T03:50:09Z")
From my Army days I remember it being called a blasting machine. [http://images.google.com/images?q=tbn:8lH6zTG6froJ:www.miningartifactcollector.homestead.com/files/U.S.Army\_10cap\_2.jpg](http://images.google.com/images?q=tbn:8lH6zTG6froJ:www.miningartifactcollector.homestead.com/files/U.S.Army_10cap_2.jpg) (if there is no picture shown, just Google “blasting machine”)