Re: TR3 Windshield Frame Question
I had a bit of trouble understanding the original photo above but them I remembered that this is inside the chromed brass frame on my early 1958 TR3A when I was last changing the glass. These threaded pads are inside the bottom of the groove up the sides where the glass slides into the frame with the rubber seal. The screws #52 are secured to the threads in the small plates that Mountainman shows above.
To help him with his problem of how to get the broken stubs of the rusty screws out of these holes, use a lot of penetrating oil and wait a day or a week, applying a bit more every day. A little heat would help, but you don't want to melt the brass of ruin the chrome. Or, as you said, you might drill them out.
I seem to remember that on my frame, these pads are brazed or silver soldered into the bottom of the groove.