In message , The Other Mike
writes

So, is it not possible to make the screw using the 7/32 BSW die from a
tap and die set starting with an M6 slotted countersunk screw where I
had removed the thread and holding it tight on a vice?

You need to remove the thread, keeping the bolt exactly round and parallel,
reducing it in size to the major diameter of the thread you are trying to
produce

7/32" BSW or 12 24 UNC are 0.216" or 5.48mm.

Given that an M6 x 1 thread is 6mm diameter and 5mm at the root you cannot
produce a 7/32 BSW thread from this as by the time the M6 thread form
is removed
the diameter of the bolt is 0.48mm smaller than that of the diameter needed for
the new thread.

Also, and excuse my ignorance, other than to clean a thread or rethread
a slightly worn out one, what use are the dies in a tap and die set for?

For cutting new theads on usually round material, exactly what you want to do
but you are starting from the wrong start point.

I suppose he might be able to grip the counter sunk head in a *soft jaw
vice*. I use off cuts of aluminium angle.




--
Tim Lamb