These square drive spindles are used with vintage style door knobs and mortise lock systems Actual size is 17/64 inch x 17/64 inch x 3-1/2 inch (does not fit 1/4 inch) This item features 3/8 inch - 20 custom thread intended for door handles Zinc plated steel construction for durability Please refer to the line art drawing for dimensions and compare with your needs before ordering 1/4in. square drive Threaded shaft For antique style knob systems Zinc finish