Square Drive Screw Square Hole Robertson Bit Self Tapping Screw

Square drive screw also is known as Robertson drive screw. The screw has a square-shaped socket in the screw head and a square protrusion on the tool. Both the tool and the socket have a slight taper. Originally to make the manufacture of the screws practical using cold forming of the heads, this taper provides two other advantages that have served to popularize the drive: it makes inserting the tool easier and tends to help keep the screw on the tooltip without the user needing to hold it there. Robertson screws are commonplace in Canada, though they have been used elsewhere and have become much more common in other countries in recent decades. Robertson screwdrivers are easy to use one-handed because the tapered socket tends to retain the screw, even if it is shaken. They also allow for the use of angled screwdrivers and trim head screws. The socket-headed Robertson screws are self-centering, reduce cam out, stop a power tool when set, and can be removed if painted over or old and rusty. In industry, they speed up production and reduce product damage. Ever Hardware provides custom-made fasteners and customizable packaging.

A self-tapping screw is a screw that can tap its own hole as it is driven into the material. For hard substrates such as metal or hard plastics, the self-tapping ability is often created by cutting a gap in the continuity of the thread on the screw, generating a flute and cutting edge similar to those on a tap. Thus, whereas a regular machine screw cannot tap its own hole in a metal substrate, a self-tapping one can (within reasonable limits of substrate hardness and depth).