From pan head to Torx — master identification features, use cases, and selection guidelines for every screw head type
The pan head has a low, rounded dome-shaped top with a slightly convex surface and rounded edges. This is one of the most common screw head types, widely used in electronics, appliance assembly, and plastic part fastening. Since the head protrudes above the mounting surface, the screw position is visible after installation, making maintenance and disassembly convenient. Pan head screws typically use Phillips or slotted drives.
Pros: Extremely versatile, readily available, suitable for applications requiring repeated disassembly. The head provides good bearing area and won't sink into soft materials. Cons: Head protrudes above the surface, unsuitable for flush-finish applications, and may cause interference in tight spaces.
The flat head has a conical shape designed to be embedded in a countersunk hole in the workpiece, sitting flush with the surface after installation. Standard countersink angles are 82 degrees (US standard) or 90 degrees (metric) — ensure the countersink angle matches when purchasing. These screws are used extensively in woodworking, metal panels, aerospace structures, and any application requiring a smooth surface.
Pros: Completely flush after installation, no interference with sliding parts or covers, clean appearance. Cons: Requires pre-machined countersink holes (drilled or stamped), adding installation steps. The conical head exerts radial wedging force on the hole wall, which may cause cracking in thin or brittle materials.
The hex head has a hexagonal prismatic shape, tightened using a wrench or socket wrench from the outside. This is the classic head type for structural engineering and mechanical assembly, commonly found in steel construction, bridges, flange joints, and heavy machinery. Hex head screws are categorized as full-thread (tap bolt) and partial-thread (hex cap screw) — longer lengths typically use partial-thread designs to reduce shear load in the threaded area.
Pros: Can withstand extremely high torque, large tool engagement area with minimal risk of stripping. No drive recess needed, so head strength exceeds equivalent recessed-drive screws. Cons: Requires lateral access for wrench or socket, unsuitable for deep recesses. Head is relatively large and heavy.
The SHCS has a cylindrical head with a hexagonal recess in the top, driven by an Allen key. The small head diameter and low profile make it ideal for precision machinery, machine tools, jigs, and mold assembly where space is limited. Material is typically heat-treated alloy steel with a strength rating of Class 12.9, making it the go-to choice for high-strength fastening.
Pros: Compact head that can be recessed into counterbores for flush installation. Hex socket provides excellent torque transfer with minimal cam-out. High strength ratings suitable for heavy loads. Cons: Allen keys are less common than Phillips screwdrivers, making field maintenance less convenient. Socket can become unusable if contaminated with rust or debris.
The button head has a low, hemispherical dome shape — flatter and wider than a pan head. Usually paired with a hex socket drive, it combines aesthetics with functionality. Common in consumer electronics housings, furniture hardware, and display fixtures where appearance matters. Its smooth profile won't snag clothing or scratch skin, offering a safety advantage.
Pros: Attractive appearance with smooth contours. Low profile reduces protrusion, suitable for human-contact surfaces. Hex socket drive provides good torque. Cons: Due to the thinner head, socket depth is limited, and maximum allowable torque is lower than same-size SHCS. Not suitable for high-strength structural applications.
The truss head has an extra-wide, very low-profile circular head — the largest bearing area of any standard head type. This design makes it ideal for securing thin sheets, covering oversized holes, or preventing screws from pulling through soft materials. Common in sheet metal assembly, ductwork, electrical enclosures, and ceiling systems.
Pros: Extra-large bearing area distributes clamping force effectively, preventing thin-sheet deformation or screw pull-through. Provides good clamping without washers. Cons: Wide head occupies significant surface area, unsuitable for closely spaced fasteners. Torque capacity is moderate.
The hex flange head integrates a washer-like flange at the base of a standard hex head. The flange face typically features serrations that increase friction when tightened, providing anti-loosening properties. Widely used in automotive engines, chassis, frames, and vibration-prone environments, as well as automated assembly lines where reducing part count is important.
Pros: Eliminates the need for separate washers, reducing part count and assembly time. Flange evenly distributes pressure, protecting workpiece surfaces. Serrated flanges provide anti-loosening capability in vibration environments. Cons: Overall height and diameter exceed standard hex heads, requiring more installation space. Serrated teeth leave impressions on soft surfaces.
The Torx drive features a six-pointed star-shaped recess, invented by Camcar (now Acument) in 1967 under the Torx trademark. The star shape dramatically increases tool-to-screw contact area, enabling higher torque transfer with virtually no cam-out. Now widely used in automotive, electronics, hard drives, and medical devices. The security variant (Torx Security / T-pin) adds a center post requiring a specialized tool, commonly found in anti-tamper applications on public facilities and playground equipment.
Pros: Maximum torque transfer efficiency with virtually zero cam-out. Extended tool life, ideal for automated high-speed assembly. Security variants effectively prevent unauthorized removal. Cons: Requires dedicated Torx drivers, less ubiquitous than Phillips and slotted drivers. Numerous sizes (T5 to T100) mean field maintenance requires a full set.
The drive type determines which tool is needed to tighten the screw. The same head shape can pair with different drive types — for example, a pan head can have either a Phillips or slotted drive. Here are the four most common drive types:
The most widely used drive type globally, featuring a cross-shaped recess. Designed with a "cam-out" characteristic — when torque exceeds the limit, the driver automatically slips out, preventing over-tightening. This is a safety feature for manual assembly but a drawback for power driving. Common sizes range from PH0 to PH4, with PH2 being the most universal.
The oldest drive type, with a single straight-line groove across the head. Simple structure, low manufacturing cost. Main disadvantage: the driver easily slips sideways, making it unsuitable for power tools or high-torque applications. Now primarily used in low-load decorative screws, electrical terminal screws, and scenarios where a coin or flat tool can serve as a driver.
A hexagonal recess paired with an L-shaped Allen wrench. Provides excellent torque transfer with affordable, durable tools. The L-shape allows force from either end — the long end reaches into tight spaces, while the short end provides more leverage. Metric and imperial sizes are not interchangeable — using the wrong size will damage the hex recess.
A six-pointed star recess offering the best torque transfer efficiency and lowest cam-out risk. Common sizes range from T5 (micro electronics screws) to T100 (heavy machinery). Increasingly replacing Phillips drives in automotive and electronics. When purchasing, note the difference between standard Torx (external six-star) and Torx Plus (optimized star shape for increased contact area).
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Simply take a photo and upload it — Screw Genius tells you within seconds what type of screw you're holding and what tool to use. Whether it's a Phillips pan head, countersunk Torx, or socket head cap screw, the AI can accurately identify it and help you quickly find the right replacement or tool.