Cut Off or Defect?

[Glassman]

Anyone ever see an insulator like this? Apparently it's a CD-147 with the top cut off. It's not only a clean slice but it's angled downward and kind of convex. Could it have came from the factory like this?
Ralph

 

[botlguy]

It's caused by water getting into the threads and freezing. It pops the top right off of them. It almost always looks like that because that is the weakest point of the insulator. I've had it happen many times to insulators left outside upside down.

 

[RED Matthews]

FACINATING, I have quite a few insulators and I have always been fascinated with the hand screwed in threads and the glass pushed up ( or actually down in the used insulator) by the excess glass left inside the skirt systems. I haven't seen much coverage of them in books on early glass. I have a blog on mine started and hope to work on it, next summer while in NY.
I am also interested in some pictures of insulators that were poured solid in the mold to heat up the mold iron. This was also done in a lot of bottle and jar molds, but I have never been fortunate enough to examine and hold very many of them in my exposure to glass collecting.
RED Matthews

 

[Glassman]

Thanks Jim, I never would have thought that could happen. It was in a batch of insulators I inherited.

Ralph