Winged self-drilling have thin wings wider than the thread formed just behind the self drilling head. These cut a clearance hole in soft materials (such as wood or plastic), but are destroyed by more robust materials (such as metal). Thus, to clamp some material to metal, the clearance drilling, tap drilling, thread tapping, and fixing itself can happen in a single operation from one side, with the materials in their final position. [10] Applications [ edit ]

Grub screws: work using a pinning action that pushes two surfaces against each other, negating the need for a nut. They are often used in applications requiring a small, unobtrusive screw. A self tapping screw is a type of screw that taps a hole (creates a thread) as you drive it into a material. Self tapping screws some of the most commonly used fasteners because they’re very useful. In fact, they’re so commonly used with soft metals that they’re often referred to as sheet metal screws. Masonry screws are available in zinc, carbon steel, hardened steel, and high tensile steel. They have an anti-corrosive coating and are tarnish-resistant, making them suitable for outdoor use. They’re available in gauge sizes ranging from 3 to 10mm and lengths ranging from 16 to 200mm. I found that a good starting technique was to hold the handle close to my body, and turn with my hips, keeping my hands in the same relation to my body the whole time. I kept my eye on the end of the tap where it was held in the handle, and concentrated on that not moving sideways. After the tap has set it was fine to ease off on this and turn by hand.When choosing the thread, consider the density of the timber. It’s best to use fine threads for hard timber and coarse threads for soft timber. The hex head allows for firmer tightening than other screw options, making it suitable for fixing things like rails and wall plates. Tapcon Countersunk Head Screws have many advantages - they can be installed close to edges, they are removable and adjustable, fire resistant and can replace small diameter expansion anchors, plugs and screws in light to medium-duty applications. Some prefer to use somewhat arbitrary but reliable formulas like: “Dtap = Nominal Diameter – Thread Pitch”. This formula works for both metric and imperial units, and for all 60-degree threads (all ISO, DIN, UTS, UNC, UNS, and UNF bolts). The first tap drill chart below is in mm and the next in inches. Both are available as a printable tap drill chart PDF as well. Tap Drill Chart (mm and inches)

To use self-tapping screws, place the screw directly on the aluminium sheet. The screw's sharp point will make its own hole. Stabilise the screw so it doesn't tilt as it is put in. Let the screw turn until it goes through. Take care not to over-tighten the screw as this can damage the metal or break the screw. Tap in a wrench for creating female threads (left), and die in a wrench for creating male threads (right).Woodscrews are available in a range of materials such as carbon steel, hardened steel, zinc, stainless steel and solid brass. Brass is usually chosen for its appearance when combined with brass ironmongery such as hinges and door handles. Stainless steel is ideal for areas exposed to moisture, and carbon and hardened steel can be fitted without needing pre-drilled holes. In addition, all wood screw materials have high levels of corrosion resistance. They are available in gauge sizes ranging from 3 to 8mm and lengths from 12 to 300mm. Locate Utilities - Ensure there are no electrical, plumbing, or gas lines in the vicinity of your drilling and installation area.