Special screw to secure the butterfly valves in a series of Solex carburetors.
This concerns the version that is 9,5 mm long and has 4 millimeter standard metric thread with a conical head.
To prevent them from working themselves loose, the end of these screws can be "peened" or "staked" which the widening of the protruding end by use of a hammer and a center punch with a conical point.
To facilitate this peening, the nose of the screw has been drilled out, as can be seen in the photo.
As Solex is notoriously bad documented, these screws probably fit a myriad of other (Solex) carburettors but we have no cross reference lists.
If you order these screws, please make sure that they are the correct version and size for your purpose.
Required quantity per butterfly valve: 2