A screwy collection -[ HMM ]-

A 4-40 machine screw collection in a mix of head styles and lengths..Each screw is of the same outer diameter (#4, 0.112" or 2.845mm) and thread pitch (40 threads-per-inch density, a pitch of 0.025" or 0.635mm).

 

I have always taken the North American thread sizing standard for granted, but until I wrote this description, I did not know it had a name: the Unified Thread Standard. Ah, the benefits of research. :)

Done