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Sheet metal screws have large threads for use in sheet metal.

Self drilling, self tapping and stitching screws for all your fastening needs in siding, decking and roofing. Screws for metal cladding, light ventilated façade and sandwich panels.

General

Usually threaded all the way to their head, these will work in wood, but wood screws shouldn’t be used in metal (this is based on hardware store employee advice, not experimental evidence). Most of these screws are self-tapping in that they only require a pre-drilled hole (pre-drill sizes), but some come with self-drilling (shown in above pic) or self-tapping tips.

Product types

Self-tapping

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 hardnessand depth). For softer substrates such as wood or soft plastics, the self-tapping ability can come simply from a tip that tapers to a gimlet point (in which no flute is needed). Like the tip of a nail or gimlet, such a point forms the hole by displacement of the surrounding material rather than any chip-forming drilling/cutting/evacuating action.

Self-forming

Thread-forming screws deform the plastic into which they are driven, producting a permanent thread. They are ornarily less expensive and the threads they produce offer the highest resistance to backout.

Self-drilling

Thread-cutting screws physically remove material, in the same fashion as a machine tap, to form the thread pin. The screws’ cutting action means torque needed foe insertation is low. The screws are used in materials where disruptive internal stress are not wanted, or when it takes to too much driving torque to use thread-forming screws.

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Thread rolling screws Self-drilling screws Self-tapping screws