Threaded tube for lamp

[Iwilldoit]

Here it all is and you then screw on top the first pole. There just isnt enough thread sticking up and the cast it screws into is thin and weak. So gluing a nut in may work

 

[jj4091]

Unscrew the nut in your last pic. and take it alomg with the tube to an ironmongers or similar or electrical wholesaler, you should be able to get some somewhere as it looks like the sort of size you often see in electrical fittings.

 

[SUNRAY]

So some useful information in recent posts.

Ok I have some pictures
You can see how weak and thin the cast is.
This first photo I could break off the right hand wall of the remaining thread and epoxy in place a nut. to line it up I can just put the nut on the old threaded tube and screw in the tube into the 1/2 inch thread that remains then fill the whole segments you see with epoxy. The segments are only about 1.5 inch deep and have a closed end at the bottom

If the material is that delicate, I'd consider my suggestion as glueing any form of nut in place may be very unreliable. I'd also consider filling the casting with epoxy to strengthen it but ensure you leave enough space for the nut.
Am I right to assume the white pole comes off the casting quite easily?

I reckon best bet: https://www.ebay.co.uk/itm/188301589766? Other offers may be better value

 

[Iwilldoit]

So some useful information in recent posts.

If the material is that delicate, I'd consider my suggestion as glueing any form of nut in place may be very unreliable. I'd also consider filling the casting with epoxy to strengthen it but ensure you leave enough space for the nut.
Am I right to assume the white pole comes off the casting quite easily?

I reckon best bet: https://www.ebay.co.uk/itm/188301589766? Other offers may be better value

The broken cast end fitting is supposed to be secured with a grub screw but there is not one there, I have tried to remove it with some pipe grips but its really tight so decided best to leave it in there.
I think you are right with the nut repair but will get a full size nut and just have to make sure its not too deep and catch the lock nut.
I can thread the nut on the hollow tube then screw that into the remaining thread then fill the segment voids with epoxy covering the new nut then when it has set, unscrew the hollow tube leaving the new nut in place.
Just hope that the threaded tube is indeed M12

 

[SUNRAY]

The broken cast end fitting is supposed to be secured with a grub screw but there is not one there, I have tried to remove it with some pipe grips but its really tight so decided best to leave it in there.

That's a shame

I think you are right with the nut repair but will get a full size nut and just have to make sure its not too deep and catch the lock nut.
I can thread the nut on the hollow tube then screw that into the remaining thread then fill the segment voids with epoxy covering the new nut then when it has set, unscrew the hollow tube leaving the new nut in place.
Just hope that the threaded tube is indeed M12

Will you have space to get a full nut in there?

If it helps identify your thread, some car wheel nuts are M12 x 1.25mm

 

[Iwilldoit]

That's a shame

Will you have space to get a full nut in there?

If it helps identify your thread, some car wheel nuts are M12 x 1.25mm

Yes I think there will be enough room or I can grind down the nut on my bench grinder just need to make sure it does not foul the half lock nut.
That's a good call on the wheel nuts I have some spare somewhere and I will have a look thanks.
Just checked and you are right the nut off the hollow tube fits my wheel nuts confirming that the tube is M12 - brilliant