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

The Flat Undercut is used instead of the standard flat head for some short sizes. The 100-degree kind enables more shallow countersinking than standard 82-degree flat heads. Hex The ‘square’ head is a suitable choice for applications that require more torque. It is most often used for switch coverings Truss The round washer is a screw head which provides a larger bearing surface in applications where a round head is preferred. It is quite similar to the Modified Truss head style. Square (Set Screw)Round heads were historically the preferred fastener design because they were easy to make; most historical rivets have been made with this head design. Today the round head is generally reserved for rivets, hammer drive and wood screws. Round heads have a high crown and deep recess but the head diameter is smaller than a pan. Round head screws are shaped almost like a one-third circle with a flat bottom. . . .. A Phillips tamper-resistant screw is just like a Phillips drive screw with one big exception. It includes a small pin in the center of the screw drive that prevents you guessed it tampering.

Slot design limits the amount of torque that can be applied, making it less secure for high-tension applications If you use flat head screws in finishing, consider using a flat head screw cover (aka “beauty cap”) to hide the head (not all drive types accept screw covers). Manufactured from plastic, these caps are available in standard colors to match commonly used plastic laminates and wood. Machine screws have a wide range of applications in industries like manufacturing, construction, automotive, electronics, and more. They come in various sizes, thread pitches, and head types, allowing for versatility and compatibility with different types of machinery and equipment. Mushroom head screws are also called roofing bolts. They are very similar to the Truss head but with a cross drive on the head. The configuration has design weaknesses and as such the product is only used where strength is not a requirement.It’s rare to find Pozidriv screwdrivers in the United States, as they are much more commonly used in Europe. 25. Star-shaped heads A hex head machine screw can be tightened or loosened with a hex wrench. The slotted drive is added to make it easier to remove. One Way Tamper Proof Truss headed screws also go under the names of Oven head, or Stove head Has a low, large diameter rounded top with a flat bearing surface. Weaker than Pan heads or round heads but preferred in applications where minimal clearance exists above the head. Truss profile provides a trim finished appearance and can be used to cover large clearance holes in sheet metal

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 Raised heads, sometimes known as oval-shaped heads, have an angle much like flat screws but have more of a dome-shaped head. You’ll also need to countersink these screws to accommodate the angle. Truss head screws are designed to protrude out the surface into which they are driven. They have a wide, rounded head. Driving a truss head screw into the surface of an object will result in the head protruding out. Truss Head vs Pan Head Screws: What’s the Difference? Metric Oval is a rounded head with a 90° is a countersunk cone-shaped bearing surface. Preferred over a flat head in conical applications, or when a more decorative finished look is desired. The countersunk surface nests into mating countersunk applications. Inch Oval is the same as metric but with an 82-degree cone. Button screw heads come in a variety of sizes and lengths, and their common characteristic is a small, round, button-shaped head, hence the name. They can be flat or slightly rounded, but they always have heads that look like small buttons.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 A binding undercut machine screw has a rounded top surface with slightly tapered sides. The bearing surface is flat and the slotted type has an annular undercut adjacent to the shank. The binding head style is the preferred design for making a firm electrical connection. Button

The ‘pan’ head is the most commonly used rounded-top screw head. It works well in a range of applications that require a flat-bottomed screw. Hex Washer 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. Bugle heads are used mainly on screws made for plasterboard and drywall. This shape is much like a flat screw head, except that, instead of an angle underneath the surface of the head, you’ll see a curved shape that can reduce damage to a surface.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 Each head will have an additional pin in the design that requires a special tool to install and remove. A Phillips screwdriver will not work to install or remove a tamper-resistant Phillips screw. 33. Sentinel Screws