Cutting open a spark plug? No way.

[Bill Kahn]

Yes, I like to try to make stuff. I also have a great time trying to take things apart. An old laserjet. An old washing machine (simply amazing main motor deep in there. ) And recently an old lawn mower. So, what's inside the spark plug? I mean, seems simple enough to imagine. But it is always a blast to cut things open. So, throw it on the 4x6 HF and...whoa...this is not like cutting other stuff. That porcelain (or whatever that insulator is) is way harder than my bi-metal saw blade. OK, throw it into the lathe with a carbide tool. Crack. Must have been a weak insert. Put in the other side. And, crack again. Some lessons just have to be learned empirically. OK, enough is enough. Put onto the floor, faceshield, and hammer it. Yup, that works. Not sure I really saw the beauty of the insides, but that spark plug, while not being "taken" a part has certainly ended up in parts (well, maybe pieces would be a more accurate description.

So, how do folks with smarts or talent slice open a spark plug? What tooling/equipment does that?

In taking stuff apart I am simply amazed at how smart mass production is. A million times smarter/more efficient than I could ever be.

-Bill

 

[kd4gij]

Diamond saw blade like a tile saw

 

[FOMOGO]

X2, get a cheap Walmart diamond blade for a 4" angle grinder. Should cut like butter. Mike

 

[Old junk]

Diamond blade.

 

[benmychree]

The metal part that is crimped over to retain the core can be turned back in a lathe and the porcelain pulled out.

 

[whitmore]

Diamond or other abrasive should work; zirconia and aluminum oxide are both common abrasives, and
are candidate minerals for the ceramic in a spark plug. Hardness is difficult to quantify, but the (old,
traditional) Mohs scale calls 'em hardness 8 for Zirconia, 9 for aluminum oxide. Diamond is 10.

 

[Dave Smith]

diamond blade is fine for the ceramic but won't last long cutting the metal--benmychree has the way I do it--funny why so many of us just love to take weird items apart for reuse or just curiosity---Dave

 

[cathead]

Some of the very early spark plugs you actually can actually disassemble. They have a second hex at the base of the porcelain and allow one to take it apart.









https://www.hobby-machinist.com/threads/cutting-open-a-spark-plug-no-way.68721/#top
This one you can take apart AND put it back together.

 

[ultrapan]

My motorcycle plugs can be disassembled and cleaned

 

[Manderioli]

Are you trying to literally split a spark plug in half?