Marine Machine Screw

About product

Marine machine screws are essential for securing components together in boat applications. With an excellent selection available, most are made of stainless steel for corrosion resistance. Unlike wood screws, machine screws are designed for through-bolting purposes. They are commonly used to secure a deck to a hull and to fasten hardware onto a deck. Machine screws come in various thread lengths, diameters, thread counts, head types, and drive types to suit different needs.

Marine Machine Screw Drawing

Additional information


stainless steel



Product Detail

Specifications and Measurements Of Marine Machine Screw

Machine screws come in different specifications to accommodate various needs. They are available in coarse (UNC) and fine (UNF) threads, with right-hand threads being the standard (clockwise to tighten). The size (diameter) ranges from #0 (very small) to #12 and 1/4″ to 1/2″. There are nine common head styles, including two countersunk styles, and four drive styles. Three common materials used for marine machine screws are also available.

Measurements for machine screws depend on the head style. For flat heads, the length is measured from the top of the head to the tip of the thread. Oval heads are measured from the edge where the dome top meets the sloping bearing surface to the threaded tip. Other head styles like Binding, Fillister, Hex and Hex Washer, Pan, Round, and Truss are measured from under the head to the screw’s tip. Length is specified in fractional inches.

Head Types Of Marine Machine Screw

Head Types of Marine Machine Screws:

  • Binding Head: The binding head features a low-profile, rounded top with a wide bearing surface. It is designed to distribute the load evenly and provide a secure connection. Binding head machine screws are commonly used in applications where a low-profile head is desired.
  • Fillister Head: The fillister head has a slightly rounded top with a cylindrical shape. It offers a larger bearing surface than flat head screws, providing increased resistance to pull-out forces. Fillister head machine screws are often used in applications where a flush or countersunk appearance is not required.
  • Flat Head: Flat head machine screws have a flat top surface with a conical bearing surface angle of 82°. They are designed to sit flush or slightly below the surface when installed, creating a neat and finished appearance. Flat head screws are commonly used when a flush finish is desired or when countersinking is required.
  • Hex Head & Hex Washer Head: Hex head machine screws have a hexagonal head with six flat sides, allowing for easy and secure tightening using a wrench or socket. Hex washer head machine screws have a built-in washer-like flange under the head, providing additional bearing surface and eliminating the need for a separate washer. Both hex head and hex washer head screws are known for their high torque resistance and are widely used in marine applications.
  • Oval Head: Oval head machine screws have a rounded top with a tapered, slightly flattened shape. The oval head provides a decorative appearance while still offering a countersunk feature for flush installation. Oval head screws are commonly used in applications where a decorative and low-profile head is desired.
  • Pan Head: Pan head machine screws have a rounded, slightly domed top with a flat bearing surface. The pan head design offers a larger contact area, providing increased resistance to pull-out forces. Pan head screws are versatile and commonly used in a wide range of marine applications.
  • Round Head: Round head machine screws have a domed top with a slightly larger bearing surface compared to pan head screws. The round head design provides a decorative appearance and increased strength. Round head screws are commonly used when a decorative finish and higher load-bearing capacity are required.
  • Truss Head: Truss head machine screws have a low-profile, wide head with a rounded top and a flat bearing surface. The truss head offers a larger contact area and increased resistance to pull-through forces. Truss head screws are often used in applications where a wide bearing surface and high strength are necessary.
  • Miscellaneous: This category includes various specialized head types that may be specific to certain applications or industries. These can include specialty heads like socket head, button head, or flange head screws, among others.

Usage Tips and Considerations Of Marine Machine Screw

To create a countersunk recess for flat and oval heads, it’s important to use a matching countersink with the appropriate angle (82° or 100°). The body diameter of the countersink should be equal to or greater than the head diameter to ensure a uniform bearing surface.

Machine screw flat washers can be used to increase the bearing surface of the screw’s head or nut. This is particularly useful when working with soft materials or oversized/irregular-shaped holes.

In addition, slotted flat head and slotted round head machine screws are sometimes referred to as stove bolts when supplied with hex nuts, offering versatility in certain applications.

Marine Machine Screw Size Chart

SizeNominal Thread Diameter
Decimal/"Nearest Fractional/"
Know Who We Are

About our company

Zava Marine Corporation is a leading supplier of marine parts and components. With a strong focus on quality and customer satisfaction, we specialize in providing a comprehensive range of high-quality marine equipment and accessories. Our products include deck equipment, ship accessories, and various other essential components needed for smooth maritime operations.

With a global presence, we serve a diverse customer base, including shipbuilders, shipowners, offshore operators, and marine equipment distributors. We are committed to providing exceptional service and tailored solutions to meet our customers’ unique needs.


Zava Marine offers a comprehensive range of certifications for marine parts in accordance with international standards and regulations. These certifications include those provided by renowned marine classification societies such as Lloyd’s Register (LR), Bureau Veritas (BV), China Classification Society (CCS), Registro Italiano Navale (RINA), American Bureau of Shipping (ABS), Nippon Kaiji Kyokai (NK), and Det Norske Veritas – Germanischer Lloyd (DNV-GL). By collaborating with these esteemed societies, Zava Marine ensures that our certified marine parts meet the highest standards of safety, quality, and performance, instilling confidence in our reliability and compliance within the maritime industry.

The warranty provided by Zava Marine covers defects in materials and workmanship for a period of two years from the date of purchase. During this warranty period, if any marine parts purchased from Zava Marine exhibit issues or failures resulting from manufacturing defects or faulty materials, Zava Marine will take responsibility for repair or replacement of the affected parts. 

Zava Marine has recently opened new molds for European and North American clients, utilizing materials such as metal, ABS, PVC, and more. These successful mold opening projects allow us to provide customized marine parts and components that meet the specific requirements of our clients in these regions.

Typically, Zava Marine can ship samples within 7 days once the product drawing has been mutually confirmed by both parties. This efficient process ensures that customers can receive samples promptly, allowing them to assess the quality and suitability of the products.

Zava Marine frequently utilizes a wide range of materials in our projects. These materials include aluminum, stainless steel, carbon steel, copper, plastics, titanium, and PEEK (Polyether Ether Ketone). Each material offers unique properties and characteristics suitable for various marine applications. 

Yes, we provide customization services for marine parts. We understand that every project and application may have unique requirements, and we are committed to delivering tailored solutions. By collaborating closely with our clients, we can adapt our products to specific specifications, ensuring optimal fit, performance, and compatibility. Whether it’s modifying existing designs or creating entirely new parts, our customization services cater to the diverse needs of the maritime industry.

Absolutely! We offer product design and development services to support our clients’ needs. Our experienced team of engineers and designers can collaborate with clients from concept development to final product realization. By leveraging our expertise in marine engineering and design, we can provide valuable insights and innovative solutions. Whether it’s optimizing existing designs or creating entirely new products, we are equipped to assist clients in bringing their ideas to life efficiently and effectively.

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