Screw Drive Types
There are three basic drive types in woodworking. Two of them are very common.
- Phillips drive - Phillips drive has the plus pattern. It was designed as a torque limiting drive. When enough torque is applied to the screw, the drive bit should slip out of the screw head. In woodworking there are two primary sizes. Phillips #2 and #3.
- Square Drive (or Robertson) - This screw holds in the driver very easily, making it easy to drive screws one handed. The screw does not typically fall off the driver bit. In addition, it is very hard for the driver to slip on the head.
- Combo Drive, Phillips/Square, Quadrex - This is a combination of the Phillips drive and Robertson Square drive. While either driver can be used to drive these screws, there is a special driver bit which fits the entire pattern and maximizes the torque transfer.