Pitch: The pitch will be the axial distance between two adjacent threads measured parallel for the axis. It can be equivalent to one/amount of threads per inch. Square- Square recess screws Possess a square-shaped socket in the center on the screw head. They're also a little tapered making set up https://typesofmetalceiling74052.tkzblog.com/29269873/the-ultimate-guide-to-types-of-screw-heads-names