I made my own, with difficulty. You need a short length of steel tubing which you need to shape to a triangle with a small hammer, and then finish off by driving in one of the triangle screws.
Better still. Get one of the screws as a pattern and match it to a baby socket, then grind down the outer circumference of the socket to go into the lamp. This will shift a tight one.
Beware of trying pointed pliers in the lamp, you will crack it!
Later lamps use an allen key.
My avatar is a poor likeness.