Several kinds of screwdrivers use triangular shapes. Most of these triangular drivers, and the screws or nuts for which they are designed, appear in security or tamper-resistant applications. Because of their unusual shape, and the small number of companies that manufacture and distribute them, triangular screwdrivers are ideal for situations where screws and nuts cannot be easily removed. However, there are only a limited number of variations on the triangular screwdriver style.
Shaped like the letter "Y," the tri-wing drive was originally developed for the aerospace industry. However, it is used for a number of home applications, especially in toys for children and video game systems.
The Delta drive takes the shape of a solid triangle. Also known as a recess-triangle, this type of drive is used most often in railway and fire applications. For example, the driver is used to install special screws in train doors and fire hydrants. Its use as a security or tamper-proof tool relies on the scarcity of delta head screwdrivers.
This proprietary product provides a common alternative to delta drives. The slightly rounded triangular shape of the drive makes its corresponding screws and bolts more difficult to remove using even a delta head screwdriver. This contributes to its popularity in security or tamper-proof applications.
Almost exclusively used for electrical systems used in mining, triangular nuts and nut drivers recess the triangle into the driver, rather than the nut or the bolt head. The tip of the driver resembles a triangular socket that slips around the solid triangle of the nut.