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The Differences between Self-Tapping and Self-Drilling Screws

By smc editor - 03.11,2013

Usually, when people are talking about self drilling screws and self tapping screws, they always think they are almost the same. But actually they describe two completely different types of screws. To some extent, understanding the differences between self drilling and self tapping screws is vital to viewing construction tasks. If people use wrong type of screw fastener, that will result in weaker joints between materials and cause structural failure.

Self-Drilling Screws
• Self-drilling screws are the most common type of screw. Self drilling screw is a fastener that does not require a predrilled hole. Screws have a tapering shaft with a continuous thread running from the point toward the screw head. The term "self-drilling" describes that the screw can drilling itself into a material; however, there will be necessary to have a pilot hole to start a screw. It also means Self-drilling screws create their own hole and form their own mating thread in the process.

Self-Tapping Screws
• Self-tapping screw is a screw with a hardened thread that makes it possible for the screw to form its own internal thread in sheet metal and soft materials when driven into a hole. The term "self-tapping" describes the screw is capable to drill a pilot hole, which is also known as "tapping" a material. Self-tapping screws are ideal screws for drilling into metal and other hard materials, but are not useful for soft materials.

Self-Drilling Applications vs. Self-Tapping Applications
• You will find self-drilling screws are common in woodworking projects, and applications involving thin or soft metals. Self-drilling screws are also common in projects where pilot holes already exist.
• Self-tapping screws are preferable used in situations where the screw pattern is not pre-drilled, or there is no specific screw pattern. Self-tapping screws are useful for fastening metals, including steel, aluminum and brass.