I needed to replace some screws in a metal door hinge where I work They
must have used some odd ball size. I tried a #6 metric and it almost fit
but didn't. Went to a 1/4 inch in the two number of threads and it was too
big. The next size I could find was a # 12 and it did not fit. The #5
metric was too small. I found a new package of hinges with the screws and
they fit fine.

What are they using for the screw size in a metal door ?