This Screw is typically fitted to Villiers armature plates, retaining the ignition coil in most cases.
Suitable for the 8E / 6E / 30C ignition coil in most examples (2 Required)
Also fits some of the other engines, 1F, 2F, 10D, 12D etc.
Specs are :
5/32 Whit thread
Designed for counter sunk hole