different combinations: Flat head screws can be used together with flat spacer spring pads depending on the actual use because the connection is at 90 degrees. Countersunk head screws can only be added with shims with taper.

Flat head screws have a flat head and slotted cross slot, hexagonal, etc. Flat head screws and workpiece contact surface is a flat bit surface, flat head screws have a larger force surface, and flat head screws can be exposed or sunk in the hole during in...