Just in case some folks are not aware of this.... screws come Imperial and Metric, in a MULTITUDE of diameters, TPI (Threads per inch), as well as lengths. if you do not get a screw of the right diameter and TPI it will either not fit or will damage the threads in the hole.
My Collection of Victorian machines is the worst in this regard because most were made before the SAE and Metric standards were set, so they can be whatever the factory decided to make for that part... I have had to take careful measurements and manually reproduce three different screws so far..