Which type of threading on a fastener provides the strongest connection?

Fine thread fasteners are designed with closely spaced threads, which provides a larger surface area for adhesion and improved resistance to stripping. This additional surface area enables finer threads to handle higher loads without deformation, making them particularly strong in applications that require precision and tightness.

Furthermore, the geometry of fine threads also supports better torque retention, which is vital in maintaining clamping force across the joint. This characteristic is crucial, especially in environments subject to vibrations where less likely loosening of the fastener is desired.

In contrast, coarse threads, while providing better engagement in softer materials and quicker installation, do not offer the same level of strength as fine threads when it comes to load distribution and resistance to mechanical fatigue. ACME and square threads serve specific purposes like transmitting motion in screw mechanisms rather than providing the strongest fastening solution.