Stainless steel nuts, bolts and screws: A2 - AISI 304

What is the difference between A2 and A4 stainless steel?

A4 stainless steel (AISI 316) contains molybdenum, which makes it significantly more resistant to chloride corrosion (such as sea salt) than A2 (AISI 304). A2 is sufficient for many nautical applications, but A4 is preferable in more aggressive environments or for critical components constantly exposed to saltwater.

How can I protect stainless steel fasteners from galvanic corrosion?

Galvanic corrosion occurs when two different metals are in contact in the presence of an electrolyte (such as saltwater). To avoid it, use nylon insulating washers between the screw and the material to be fixed. Also, apply a specific marine-grade dielectric grease to the threads to create a protective barrier.

Is it suitable for my Suzuki DF40?

A2 stainless steel screws are suitable for most applications on marine engines, including Suzuki DF40s. However, it is always essential to check the dimensions, thread type, and technical specifications required by the engine manual to ensure correct and safe installation.

What is the difference between standard and fine pitch?

The pitch refers to the distance between the threads of a screw or bolt. Standard pitch is more common and offers greater tensile strength. Fine pitch, on the other hand, has closer threads and offers greater precision and tightness, especially in applications subject to vibration. The choice depends on the specific application.

How to choose the correct length of a screw or bolt?

The correct length depends on the thickness of the materials to be fixed and the thread depth required to ensure a secure hold. It is important that the screw or bolt extends completely through the materials to be fixed and screws firmly into the nut or threaded hole. If in doubt, it is always better to opt for a slightly longer length.