this kind of screw is really a non-structural fastener. It is supposed to be tightened and loosened by hand using the ridged sides. Some are also made having a key-like flat facet or fashioned for flat or Phillip head https://types.blog/types-of-screw-heads/
types of screw heads for Dummies
Internet 2 hours 23 minutes ago hamzahmjud126734Web Directory Categories
Web Directory Search
New Site Listings