Hows, Whys, and Wheretofors

[Geisterlibrarian]

This may get moved, but I am wanting to bring out the latent Professorial talent in this group.

I was reading some thread or another, and a gentleman posted a nice picture of the filament of a lightbulb which he smashed and then magnified for his son to learn from.  The filament was a coiled coil (?) or spiraled coil, or coiled spiral or something.   

The immediate question I had was - Why?  (I'm assuming it is done to make the light brighter by exposing more surface on the filament, but I don't know.)   The next question I had was - How?  How was it made?  Could I do it?  (and on that I have no clue.)

I imagine there are lots of questions that people have about fairly ordinary stuff which could be answered by others on this board.

Here's a few of mine to get started - (also, the one above about the lights is still fair game.)

How do they make metal slinkies?  Do they extrude them out already in a coil? (if so how?) Are they flat wire that's then bent sideways into a spiral? (seems stressful to the wire) Or are they solid-sided cylinders which are then shaved/peeled into a coil? (seems complicated) Does anyone know? 

There's a type of engine which is designed to mis-fire.  They use it for ice-cream churns at County Fairs around here (South Carolina).  It sounds almost painful to me to hear it miss and cough and sputter.  I'm assuming it's done on purpose - How do you do that?  Does it hurt the engine?  Why on earth would you make something that intentionally messes up?  (other than to attract attention that then eats your ice cream....)

Any one else got random questions?  Or random answers?  (42)   

I could always look on Wikipedia, but I've found that I like answers better when I can ask more questions.

Enlighten me/us, oh gurus of the Steam!

[rogue_designer]

My understanding is that a longer coil of tungsten wire increases the resistance, and therefore glows brighter (But uses more current).

The original filaments were hand rolled. I assume that it was not long before a machine was created that did a more consistent job.


Regarding a slinky. Spring steel wire is flattened and coiled in one pass of a particular machine. It is crimped by hand on the other end of the machine.

[Jemima Annabelle Clough]

How do they make metal slinkies?  Do they extrude them out already in a coil? (if so how?) Are they flat wire that's then bent sideways into a spiral? (seems stressful to the wire) Or are they solid-sided cylinders which are then shaved/peeled into a coil? (seems complicated) Does anyone know? 

I believe it is coiled wire.  Coiling, and otherwise working, soft metal hardens it - it would only become stressful to the wire if it is overworked, in which case it goes brittle, then snaps.

[Dr cornelius quack]

Some of the first lightbulb filaments were made from a single wound coil of carbon. These can still be got from scientific equipment suppliers and give a very pleasing light.
The coiled coil tungsten filament does indeed serve to give an overall resistance adequate to glow more brightly, the high melting point of the metal allows it to become white hot without breaking.
The high resistance of the lamp actually reduces the current flowing though it in accordance with Ohm's law.

Now how do they make slinkies?

Well they are individually hand carved from tubes of spring steel by highly skilled dwarves with very small files.

I think.

Dr. Q.

[Herr Döktor]

Slinkies? I heard they are he skellingtons of baby iron snakes, similar to the adult iron snakes that run in the Lun Dun Underground to this day.

[jringling]

There's a type of engine which is designed to mis-fire.  They use it for ice-cream churns at County Fairs around here (South Carolina).  It sounds almost painful to me to hear it miss and cough and sputter.  I'm assuming it's done on purpose - How do you do that?  Does it hurt the engine?  Why on earth would you make something that intentionally messes up?  (other than to attract attention that then eats your ice cream....)

Commonly known as hit-n-miss engines, they do not miss fire, but are designed to run like that

. Through the use of a centriplical (sp?) governor, the engine speed is maintained through a series of firing and freewheeling. The freewheeling is allowed through some sort of compression release, usually by holding the exhaust valve open. When the engine slows below the set speed, a mechanism allows compression and fires the engine. The engine reaches speed and then freewheels, when the engine slows below the set speed, a mechanism allows compression and fires the engine. The engine reaches speed and then freewheels, when the engine slows below the set speed, a mechanism allows compression and fires the engine. The engine reaches speed and then freewheels, when

And so on…

[von Corax]

Through the use of a centriplical (sp?) governor, the engine speed is maintained through a series of firing and freewheeling.

Centrifugal.

Also note that as the engine is loaded down, it will slow down more quickly and so fire more often, so maintaining speed.

I assume the concept was a simple means of running the engine at a more-or-less constant speed under varying load, without having to babysit the spark timing, long before the development of automatic spark-advance.

There are a number of collectors of these things in Southwestern Ontario, particularly members of the Tri-County Heritage Club in Ilderton.

[Dr Flonker]

How do they make metal slinkies?  Do they extrude them out already in a coil? (if so how?) Are they flat wire that's then bent sideways into a spiral? (seems stressful to the wire) Or are they solid-sided cylinders which are then shaved/peeled into a coil? (seems complicated) Does anyone know? 

I believe it is coiled wire.  Coiling, and otherwise working, soft metal hardens it - it would only become stressful to the wire if it is overworked, in which case it goes brittle, then snaps.

That's where heat treating the metal comes in.  When it gets brittle, you anneal it to soften it back up.