What are M27 Screws?

M27 screws are heavy-duty metric fasteners with a 27mm thread diameter, available in both coarse (3mm) and fine (1.5mm) thread pitches. The M27 bolt occupies a specialist position in the fastener range, larger than the widely specified M24 but smaller than the M30, making it a precise engineering choice for applications where specific load calculations demand this exact diameter.

In large diesel engine assemblies, M27 bolts secure cylinder head studs and main bearing caps, where the clamping force must be closely matched to the engine's operating pressures and thermal expansion characteristics. The M27 screw delivers the targeted tensile capacity these applications require.

How M27 Size Screws Work

M27 screws are selected when engineering analysis calls for a fastener that exceeds M24 capacity without stepping up to the larger, heavier M30. Their tensile stress area sits precisely between these two standard sizes, offering a calibrated solution for applications where over-engineering adds unnecessary weight or cost.

In offshore wind turbine foundations, M27 bolts connect transition pieces to monopile structures, enduring constant exposure to cyclic wave loading, corrosion and extreme weather. In industrial gearbox housings, M27 cap head screws secure split casings under high torque transmission loads. The coarse (3mm) pitch, shared with M24, enables efficient installation, while the fine (1.5mm) pitch is specified where enhanced vibration resistance and tighter preload accuracy are required.

Materials M27 Screws Are Made From

Our M27 screws are crafted from high-quality materials to support a variety of operational requirements:

• High-Tensile Steel: Provides exceptional strength and durability, ideal for preloaded and high-stress mechanical connections.
• 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.
• Brass: Offers excellent resistance to corrosion and is easy to machine, making it suitable for decorative and electrical applications.
• Aluminium: Lightweight with good corrosion resistance, suited to applications where weight reduction is a priority.
• Nylon and PEEK: Lightweight thermoplastics offering excellent chemical resistance and high thermal stability, used in specialist engineering projects.

Sizes and Types of M27 Screws Available

M27 screws come in a range of configurations to meet various project specifications:

• Lengths: Available in lengths ranging from 30mm to 200mm.
• Head Types: Hexagon and cap head profiles are available to suit different installation and clearance requirements.
• Thread Types: Fully threaded and partially threaded variants 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: When should I specify an M27 bolt instead of an M24 or M30?

 A: An M27 bolt is the right specification when engineering calculations show that M24 provides insufficient tensile area for the required preload, but M30 would be oversized for the joint geometry or would add unnecessary weight. It is commonly specified in engine assemblies, gearbox housings and foundation connections.

Q: What is the thread pitch of an M27 screw?

 A: M27 screws are available in coarse (3mm) and fine (1.5mm) thread pitches. The coarse pitch matches the M24, which simplifies tap selection when both sizes are used within the same assembly. The fine pitch offers a higher tensile stress area and improved resistance to self-loosening.

Q: What hex key size is needed for an M27 socket cap screw?

 A: An M27 socket cap head screw (DIN 912) typically requires a 19mm hex key for installation and removal.

Q: Is the M27 a standard metric size?

 A: Yes. M27 is a standard ISO metric coarse thread size, though it is less commonly stocked than M24 or M30 due to its intermediate position in the range. Accu maintains availability in both coarse and fine pitch across key materials and lengths, with custom manufacturing for non-standard specifications.

Bespoke M27 Screws Manufacture.

High precision, bespoke manufacture of M27 Screws to customer specification. State of the art facilities specialising in both small batch prototyping and large scale manufacture.