Tapping screws form mating threads in materials they are driven into. There are two basic types: thread forming and thread cutting. The thread-forming screw displaced material around the pilot hole so ...

They hold together everything from the most delicate watch to the largest bridge. The world is literally kept from coming apart by screws and bolts, and yet we don’t often give a thought to these ...

Twist drills do not make accurately sized or good finish holes; a reamer of some type is often used to cut the final size and finish. A reamer will not make the original hole; it will only enlarge a ...

The strength of some internal threads is more sensitive to tap diameter than previously thought. • Cold-formed threads are no stronger than cut threads when holes are correctly sized. • Cut threads ...

Self-tapping screws are designed to create their own threads as they are driven into masonry. Unlike other fasteners, contractors do need to drill a hole or tap threads in a separate step. This ...