In message , Mike Dodd
writes

The thread for a HD screw is #6-32 coarse thread (which, apparently,
during a quick google on this) is an american thread, without a metric
equivalent. Then, to contradict, someone suggests an M3.5 x 0.6mm is
equivalent - if you need to source individual screws.

They aren't all the same, I have some screws here that fit some drives,
but are too small in diameter for others.

--
Chris French