Ceiling lampshade fitting (vintage lampshade)

DavidDavidson

My grandmother picked up a lampshade for £2 from a charity shop, it's quite a nice one too. Only problem is that it won't fit a standard UK bayonet style ceiling lamp fitting where one would normally fit the shade then screw a (large, tapered plastic) ring to it.

Long story short the shade wouldn't pass the threads on the wired end of the lamp attachment as it's threaded itself. I tried screwing it in but to no avail, even after cleaning the threads and scraping out dirt from them with the point of a knife.

I measured the diameter of the threads on both the standard plastic fitting and the one built into the lampshade, the diameter of the hole between them was 2.5cm, so they were identical.

My first thought was to simply file away the old threads that were blocking the fitting, it only being a £2 shade but my grandmother didn't want that, not the plastic fitting glued to the top of the top of the shade and screw it on that way. Even the non destructive method of attaching the plastic piece to the shade using 3 bits of heavy gauge wire to hold the shade to the plastic fitting wasn't able to be done so if anyone knows how and why this isn't fitting and is able to help let me know.
Cheers and thanks in advance.
David

Here's two images of the keep in question, due to anti-spam I can't post links but if you post to imagebb all you need to do is change the end of each url. And of course if you need any more info, just ask.

/fEs3Ob


/jkaZUG

flashg67

Don't know how to view on imgBB - does one need an account?

Ectophile

http://ibb.co/fEs3Ob
and
http://ibb.co/jkaZUG
for anyone trying to find the images.

I suspect that they are near enough the same size, but different thread pitch. The shades may have been made to fit a particular lamp unit.

DavidDavidson

Thanks for the replies so far. If the lamp was designed to fit into a specific holder (I did find (new) "vintage brass lamp holders" though they're about a fiver each.
I honestly don't see why she doesn't just let the threads be filed away, leaving a perfect hole for it to slip over the plastic threads and be held by the screw on holding ring. It was a £2 lampshade (though likely worth quite a bit more), it's welded/brazed into place so I could even see if my neighbour (who had and may still have an oxy-acetylene welder to melt the weld and recover the original thread) or just use something like a wire saw to slowly cut through it until it drops off and it can be attached (probably by epoxy) if she so wills it at a later date.
She's thinking of maybe selling the house (pointless for someone of her age, being in her his eighties) and seems to think prospective buyers would be put off by it; as if prospective buyers check lampshades and can tell if it was changed carefully from its original state.


If it is as you've said and the threads are differently pitched (they looked differently gapped, as if to fit a lamp holder with much more turns of the thread per cm).