I put a big "toothpick" into the hole and twisted, and the best I found was 0,6+ pitch on a ca 3 mm hole, and do to the big .xls from Kerry , a 1/8 is very close, and it will be tested out tomorrow. As you can see from the picture, it is a very short hole. So, 55 or 60 deg is not so important.

There are some restorations on YouTube , and I will try to contact them for a picture of the head of the screw.

Johannes

Mexico