What are M16 Screws?

M16 screws are robust metric fasteners with a 16mm thread diameter, available in both coarse (2mm) and fine (1.5mm) thread pitches. Sitting at the threshold between mid-range and heavy-duty sizing, the M16 bolt is one of the most versatile large-diameter fasteners available, specified across industries from automotive and construction to renewable energy and general mechanical engineering.

In commercial vehicle chassis assembly, for example, M16 cap head screws secure suspension mounting brackets and subframe connections where high clamping force, fatigue resistance and ease of servicing are all critical. Their widespread availability and well-established material range make M16 screws a dependable first choice when engineering projects step beyond lighter M12 and M14 fasteners.

How M16 Size Screws Work

M16 screws bridge the gap between general-purpose fasteners and the heavyweight structural sizes. Their 16mm diameter delivers a substantial tensile stress area, providing the joint strength needed for demanding mechanical and structural connections without the bulk of M20 or M24 fasteners.

In steel fabrication, M16 bolts are commonly used for secondary steelwork connections such as purlins, cladding rails and bracing members, where they provide reliable load transfer in shear and tension. In packaging and food processing machinery, M16 socket head cap screws secure guarding, drive housings and conveyor frames, offering a compact head profile that minimises snag points. The fine pitch variant is often preferred in these applications for its improved resistance to vibration-induced loosening and finer torque control. Whether torqued into tapped holes or paired with nuts and washers, M16 screws deliver consistent, repeatable clamping performance across a wide range of applications.

Materials M16 Screws Are Made From

Our M16 screws are crafted from high-quality materials to support a variety of operational requirements:

• High-Tensile Steel: Provides exceptional strength and durability, ideal for structural and heavy-load applications where mechanical performance is critical.
• Stainless Steel Grades A2 and A4: A2 is a versatile option for general engineering use, while A4 offers superior resistance to corrosion, perfect for marine and chemical environments.
• A4-80 Stainless Steel: Combines the corrosion resistance of A4 with enhanced tensile strength, suited to demanding applications in harsh conditions.
• BUMAX Stainless Steel: High-strength stainless steel fasteners that bridge the gap between corrosion resistance and high-tensile mechanical performance.
• Aluminium: Lightweight with good corrosion resistance, suited to applications where weight reduction is a priority.
• Titanium: Offers an outstanding strength-to-weight ratio and excellent corrosion resistance, specified in aerospace, motorsport and high-performance engineering.
• Nylon and PEEK: Lightweight thermoplastics offering excellent chemical resistance and electrical insulation properties, used in specialist engineering projects.

Sizes and Types of M16 Screws Available

M16 screws come in a wide range of configurations to meet various project specifications:

• Lengths: Available in lengths ranging from 16mm to 300mm.
• Head Types: Cap head, countersunk, hexagon, button head and grub screw profiles are available to suit different installation and clearance requirements.
• Thread Types: Fully threaded, partially threaded and specialised options like captive screws provide flexibility for different fastening requirements.
• Drive Types: Choose from Hex Socket and External Hex drive styles to suit your tooling preferences.
• Finishes: Options such as AccuLock thread locking prevent loosening under vibration, while AccuBlack chemical blackening delivers a sleek, dark aesthetic.

FAQs

Q: What is the thread pitch of an M16 screw? 

A: M16 screws are available in two thread pitches: coarse (2mm) and fine (1.5mm). The coarse pitch is the default for general-purpose use, while the fine pitch offers a larger tensile stress area and greater resistance to vibration-induced loosening, making it well suited to precision assemblies and applications subject to dynamic loading.

Q: What hex key size fits an M16 socket cap screw? 

A: An M16 socket cap head screw (DIN 912) requires a 14mm hex key (Allen key) for installation and removal.

Q: What is the across-flats dimension of an M16 hex bolt? 

A: An M16 hexagon bolt has a standard across-flats dimension of 24mm, requiring a 24mm spanner or socket for installation.

Q: What is the difference between an M16 screw and an M16 bolt? 

A: Both terms describe externally threaded fasteners with a 16mm diameter. In common usage, "bolt" typically refers to a hex-headed fastener intended for use with a nut, while "screw" can encompass any threaded fastener, including socket cap heads designed for tapped holes. The thread specifications are identical regardless of terminology.

Q: What industries commonly use M16 fasteners? 

A: M16 fasteners are widely used in automotive and commercial vehicle assembly, structural steelwork, renewable energy installations, food and packaging machinery, general mechanical engineering and agricultural equipment.

Q: Are M16 screws available with pre-applied thread lock? 

A: Yes. AccuLock pre-applied thread-locking patches are available across the M16 range, offering reliable vibration resistance without the need for liquid threadlocker during assembly.

Bespoke M16 Screws Manufacture.

High precision, bespoke manufacture of M16 Screws to customer specification. State of the art facilities specialising in both small batch prototyping and large scale manufacture.