Author Topic: how i make spark plugs  (Read 7881 times)

Offline chuck foster

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how i make spark plugs
« on: December 12, 2009, 11:54:13 AM »
how i make spark plugs

i start off with a piece of hex bar stock for the metal part of the plug, in this case it is 1/4" hex.



i then thread the plug body to suit the engine, in this case it is #10-40 tpi.



i then make an adaptor to thread the plug body into so i can hold it in the lathe a bore out the body for the corian insulator.
 


i use an end mill to counter bore for the corian body



this next pic shows the corian loctited in place (loctite red)



i then drill a .031" hole from one end of the corian to the other and loctite a piece of .031" spring or piano wire
in the hole. this wire will become the center electrode.i leave about 1/8" of the wire sticking out of the top of the
corian insulator this is where i solder the brass plug wire terminal on.



i then make a copper washer from some copper tubing that i got from a plumbing supply place.
i just part them off on the lathe.



the last picture shows a finished plug with a ruler for size reference.



i make my own spark plugs mainly because some engines need a long or short reach plug, so as to get the spark right in to the combustion chamber.
another reason is some times on a small engine the bigger plug look out of proportion to the rest of the engine.
i have run this type of plug in several of my engines and had very little trouble. when the plug gets dirty you just take it out and rub the business end on a piece of fine emery paper to clean it.

i hope this help's those who would like to try making their own plugs.

chuck  :wave:

hitting and missing all the way :)

skype:  aermotor8

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Offline Bernd

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Re: how i make spark plugs
« Reply #1 on: December 12, 2009, 06:51:40 PM »
Nice little write up Chuck.

Makes me wonder if one could make a sparkplug for your every day driver if times ever got real bad and you needed a sparkplug?

Bernd
You can't fix "STUPID".

Offline Darren

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Re: how i make spark plugs
« Reply #2 on: December 12, 2009, 07:01:20 PM »
Thanks for showing that, I always though spark plugs were more complicated, nice to see they can be made  :clap:
You will find it a distinct help… if you know and look as if you know what you are doing. (IRS training manual)

Offline gbritnell

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Re: how i make spark plugs
« Reply #3 on: December 13, 2009, 12:39:23 PM »
Hi Chuck, nice write up. When I started out making plugs I used almost the same idea that you use. On some engines I found that the surface gap type plugs would get a little bit of condensation on them and short, on start up mainly. I then started machining mine with a ground strap. These seem to work out a little better. Rather than hijack your thread I'll start another one showing how I make mine.
George

Offline chuck foster

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Re: how i make spark plugs
« Reply #4 on: December 13, 2009, 07:22:24 PM »
mr britnell i look forward to your write up on how you make plugs.  :thumbup: :dremel:

the more ways you see something done the better, ideas can be taken from many sources and that is what makes this hobby so much fun.

chuck  :wave:
hitting and missing all the way :)

skype:  aermotor8

former hmem member

Offline sorveltaja

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Re: how i make spark plugs
« Reply #5 on: December 14, 2009, 04:47:47 PM »
Interesting work, Chuck :clap:.

Dare I ask even a bit of details of the engines, that you make the spark plugs for? :poke:
« Last Edit: December 15, 2009, 01:50:32 PM by sorveltaja »

Offline ariz

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Re: how i make spark plugs
« Reply #6 on: December 15, 2009, 03:11:24 AM »
I'm sorry, but I don't understand how it works
the main electrode seems to be immersed in the insulator and I don't see any secondary electrode from the wall of the spark plug
what am I missing?
 

Offline Bluechip

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Re: how i make spark plugs
« Reply #7 on: December 15, 2009, 05:36:15 AM »
I'm sorry, but I don't understand how it works
the main electrode seems to be immersed in the insulator and I don't see any secondary electrode from the wall of the spark plug
what am I missing?
 

Ariz

Similar to Surface Discharge Plug ..

Poke around this site .. some info on plugs in general too.

http://www.ngksparkplugs.com/products/spark_plugs/surface.asp

Commercial Item , although not as small as Chuck's plugs ..  :)

Dave BC
« Last Edit: December 15, 2009, 05:52:55 AM by Bluechip »
I have a few modest talents. Knowing what I'm doing isn't one of them.

Offline ariz

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Re: how i make spark plugs
« Reply #8 on: December 17, 2009, 10:44:19 AM »
well, now all is clear

thank you Dave  :thumbup: