Yes.
But its very rare. And i have not seen one so bad the electrode was gone from the top of the glow plug... its possible tho. Overtorqueing them can cause some interesting stresses on the electrode down hole for sure. I read a thread over on powerstroke.org, or the army about it where combined with combustion pressures, heat, and the overtorque caused the electrode to corkscrew. Wild stuff.

Chris.....think about how the GP seals and how the electrode feeds through the casting. There is a taper at the bottom of the steel hex/thread....IMO the only way for the electrode to corkscrew is an oversized electrode or an undersized hole that the electrode fits through.

I dont know where you see a taper...
I just measured one to see...

Below the machined flats... the o.d. of the plug body is .320"

Below the threads... it is also .320".

Sitting across a 1-2-3 block... the measurement remains the same from below the threads - to the end of the body.
http://i1282.photobucket.com/albums/...ps4rrk5eoc.jpg

Right at the junction of the electrode and the main body...see the 45 degree chamfer? That, I believe, is the sealing surface....btw, your 1-2-3 block is NASTY!

Lol... yes it is nasty... but it is not "mine". Most of the "shop" blocks are pretty nasty, and really only used for setting fixtures, and taking rough guide measurements. Being about 30 miles from the open waters of The Gulf makes fighting corrosion a constant battle. My blocks hardly ever come out of the box, and when they do... they get cleaned before going back in.
I keep my indicating stuff with lots of dessicant packs but i still have to fight rust.

Are you talking about the top side(connector side) or the port side?

The "beveled edge" at the bottom of the port side of the body is turned, not crimped.
The seal is(visible) at the top of the body, and doubles as an insulator.

Still digging for that other thread about the plugs getting twisted.

Looking at your picture, right hand side, directly above the second hole in the 1-2-3...that junction.....body to the getting hot part.

When I swapped my injectors i decided to do the glow plugs too. All came out nice and easy except for one. It took a little more effort but it broke loose, and after it was unscrewed and I removed the socket, all I had was the steel body. When I looked at the hole it came out of, there was the electrode sticking out. I couldn't get it out myself and had to take it to a mech (the reputable one mentioned in my previous post) to pull the head off and tap it out from the bottom side.

Not to be a total smart a$$ but that ain't no 45 degree angle and that would be the 4th hole as we read left to right, sorry couldn't resist. My attempt to be funny on only one cup of coffee. I knew what you meant.

I will have to go look at one in the garage but I was under the belief that it sealed at the threads but I am probably full of crap. It would make sense that it could corkscrew if it sealed at the bottom. The bottom could gall to the head and as the top was turned the body corkscrewed (twist), so it was probably from poor installation and not the engine that caused the one to twist up.

Ya'll are not getting what im trying to describe...
The bodies of the "twisted" plugs im talking about were straight...
The electrodes were twisted, twirrled, or corkscrew-ed. (Whichever may be the correct discriptive term...)

Still digging to find the pictures...
If i cant... i will destroy one of these two to replicate what i saw and snap a picture.

I got it now, just the heating element tip.

Yes.

I just tried to replicate what I saw and doing so proved incredibly difficult.

I got the electrode to just start to twist before the tip broke off..
http://i1282.photobucket.com/albums/...psmpfmb0sv.jpg

The ones I'm trying to describe/replicate were exponentially more exaggerated. I mean they looked like a freakin corkscrew!

So.. without a considerable amount of heat... it would not happen during removal. Even then... something down in the plug ports would have to be squeezing the tip of the plugs for torque action to twist them up.

And i just measured the beveled edge...
Its a perfect 45*.
No radius.
.020" shoulder from face.

I've read in multiple thread that Autolite glow plugs will swell up and get stuck in the heads. Maybe that's what happened?

The plugs I keep referring to were German made Motorcraft.

IMO, that is the seal.