A new variation of the Robertson drive is the Nüvo drive system. Its screws are compatible with Robertson drive tools, but have rounded lobes that, when used with Nüvo drivers, are claimed to "dramatically reduce wobbling and stripping out, enabling single-handed operation". [10] Combination screws for electrical applications [ edit ] There are many screws for different purposes: wood screws, machine screws, cap screws, self-tapping screws, drywall screws, etc. When Henry Ford tried the Robertson screws, he found that they saved considerable time in Model T production. When Robertson refused to license the design, Ford realized that the supply of screws would not be guaranteed, and chose to limit their use to his Canadian division. [4] [5] [6] Standard sizes [ edit ] Square recess dimensions [7] [8] Color A type of machine thread screw, this is basically a flat head with a rounded surface – both are countersunk. The screw head of choice for switch coverings, the oval head screw is a decorative alternative to other screws. Pan head screw Sentinel screws offer high-level protection because you can only drive them one way. They’re challenging to remove, so they’re best for permanent fixtures. 34. 2-Hole Screws

Truss heads are typically wider than the heads on other screws and have a slightly rounded surface. You’ll usually need truss heads when working with sheet metal and other projects that require large holes because the wide head prevents the truss screw from going through the hole. 8. Button Heads Some screws require matched mating parts, which means you’ll need the size of the screw thread. Examples include machine screws, which can be secured into a tapping hole or with a nut, and captive screws. Your screw thread measurement depends on whether or not you’re dealing with metric threads or unified screw threads.This screw can be screwed or driven twice the speed of other screw types due to its double thread design. These are the types of safety screws that can be determined by their unconventional drive resulting in more difficulty to tamper or take apart. These screws are primarily used in prisons to secure materials such as car license plates, gutters, and grill bars. Wrapping It Up

The flange helps the screw to remain in its position, taking the place of a washer for some projects. 7. Truss Heads Most anyone has a Phillips-head screwdriver sitting around they can use to drive Phillips screws, and the sizing of Phillips drill bits and screwdrivers is relatively straightforward. 16. Phillips Tamper-Resistant Naturally, round screw heads are those that have very round tops. They can be made of various materials and come in different designs and lengths, but they always have a round head. A dome head screw with a deep slot, these are special types of screw heads. Also called binding head screws, they typically have a 10% larger bearing surface than pan head screws. Flat – slotted head screw In this example, your M6 screw thread is 6mm x 1mm. Metric screw thread sizes are always determined by major diameter and screw thread pitch. Unified screw threads

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Similar to flathead screwdrivers, there are a wide range of sizes and lengths for Phillips screwdrivers and they also come in both manually driven and electric options. While Phillips screwdrivers do provide better control and driving power, the tip can still slip out of the screw head if it is driven with too much force. Go slow to ensure that the screwdriver tip grips the screw properly to avoid stripping the screw head. Tri-Wing screw types are somewhere between a slotted and Phillips’s drive. They have three grooves that are slightly curved and come in #1, #2 and #3 sizes. Though this screw drive type is exceedingly rare, its deep grooves allow you to apply more force than other screws. 31. Spanner The distance between each thread that makes a difference is known as the pitch. Some screws have short threads that are close to each other. And some have larger threads that are further spaced. #6 Thread Length