These taps create Acme threads, which have a trapezoidal shape and a 29° thread angle and are stronger than similarly sized square threads. Sometimes called tandem taps, Acme taps are used for threading parts that allow rotation or transversing (straight-line) movement on equipment that will bear heavy loads, such as jacks, valves, and presses. They are installed on tap holders in rigid setups such as drill presses and milling machines and are suitable for tapping through holes.