What are M36 Screws?

M36 screws are among the largest standard metric fasteners, featuring a 36mm thread diameter available in both coarse (4mm) and fine (1.5mm) thread pitches. The M36 bolt is engineered for the heaviest structural and industrial applications, where extreme clamping force and load transfer define the fastener specification.

In large-span bridge construction, M36 bolts connect primary structural members such as main girders, splice plates and bearing assemblies, where each fastener carries a significant share of the total structural load. The M36 screw represents the upper boundary of standard precision-rolled fastener sizes, serving projects where nothing less will meet the engineering demand.

How M36 Size Screws Work

M36 screws operate at the extreme end of standard metric fastener capacity. Their 36mm diameter provides one of the largest tensile stress areas available in ISO metric coarse threads, enabling very high preload values suitable for critical structural and mechanical joints.

In offshore platform construction, M36 bolts secure jacket leg connections and topside modules, withstanding the combined effects of wave loading, wind and corrosion over service lives measured in decades. In large-bore pressure vessels, they maintain gasket compression at flange joints subjected to extreme internal pressures. The coarse (4mm) pitch ensures efficient installation even at this substantial diameter, reducing assembly time on projects where bolt counts run into the hundreds. The fine (1.5mm) pitch is specified where greater tensile capacity and tighter preload accuracy are required.

Materials M36 Screws Are Made From

Our M36 screws are crafted from high-quality materials to support a variety of operational requirements:

• High-Tensile Steel: Provides exceptional strength and durability, the baseline structural grade for the heaviest load-bearing connections.
• Stainless Steel Grades A2 and A4: A2 is a versatile option for general 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 for demanding installations.
• 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 M36 Screws Available

M36 screws come in a range of configurations to meet various project specifications:

• Lengths: Available in lengths ranging from 40mm to 200mm.
• Head Types: Hexagon profiles are available as standard, with additional head types available through custom manufacture.
• Thread Types: Fully threaded and partially threaded variants provide flexibility for different fastening requirements.
• Drive Types: External Hex is the primary drive style, suited to large wrench and socket installations.
• 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 M36 screw? 

A: M36 screws are available in coarse (4mm) and fine (1.5mm) thread pitches. The coarse pitch is the largest in the commonly used metric fastener range, providing deep, robust thread engagement for general heavy-duty use. The fine pitch offers a higher tensile stress area and improved resistance to self-loosening, suited to precision-critical and vibration-sensitive applications.

Q: What spanner size fits an M36 hex bolt? 

A: An M36 hexagon bolt has a standard across-flats dimension of 55mm, requiring a 55mm spanner or socket for installation.

Q: Where are M36 bolts typically used? 

A: M36 bolts are specified in heavy structural steelwork, bridge construction, offshore platforms, large pressure vessels, power generation equipment and other critical infrastructure where maximum clamping force and joint integrity are essential.

Q: Are M36 bolts available in stainless steel? 

A: Yes. M36 bolts are available in A2 stainless steel for general corrosion resistance and A4 marine-grade stainless steel for offshore, marine and chemically aggressive environments.

Q: Can M36 screws be manufactured to custom specifications? 

A: Yes. Accu offers bespoke manufacture of M36 screws, including custom lengths, materials, finishes and head types, with capacity for both prototype and volume production runs.

Bespoke M36 Screws Manufacture.

High precision, bespoke manufacture of M36 Screws to customer specification. State of the art facilities specialising in both small batch prototyping and large scale manufacture.