Machine Screws, Marine Grade

Choosing head, drive, and material

Machine screws vary on three axes, and marine work uses all of them. Head style sets how the screw sits and spreads load: pan and round heads sit proud, flat and oval heads countersink flush, and truss heads spread a wide low profile over slotted or oversized holes. Drive sets how you turn it: Phillips is common and self-centering, while slotted suits traditional fittings and light duty, and a pinned star button head adds tamper resistance for public and exposed installations. Material is the marine decision: 316 stainless covers the great majority of head styles with full chloride resistance, silicon bronze appears on slotted styles for traditional and wood-adjacent work, and metric 316 (A4) covers metric assemblies. Match all three to the fitting, and in salt service let 316 or bronze do the corrosion work that plated steel cannot.

Why choose marine machine screws

• Full range of head styles for flush, proud, or load-spreading seating
• Phillips, slotted, and tamper-resistant star drives available
• 316 stainless resists chloride pitting across the range
• Silicon bronze on select slotted styles for traditional marine work
• Metric 316 (A4) option for metric assemblies

Common applications

• Marine hardware and fittings
• Electrical and instrument enclosures on boats
• Trim, nameplates, and cover panels
• Railings and bracket assemblies
• Tamper-resistant public marine installations (star pin-in)
• Any tapped-hole or nutted connection in salt exposure

Marine Machine Screw FAQs

What head style should I choose?

Flat and oval heads countersink flush for a clean surface, pan and round heads sit proud for general use, and truss heads spread load over larger or slotted holes. Pick by whether you want the head flush and by the bearing area you need.

Which drive is best for marine use?

Phillips self-centers and suits most work. Slotted fits traditional fittings and light duty. A pinned star button head resists tampering, useful on public docks and exposed installations. Choose by application and by the drivers you run.

Where is silicon bronze offered?

On select slotted styles, for traditional and wood-adjacent marine work where bronze is preferred for its corrosion behaviour and appearance. The majority of head styles are 316 stainless.

Is the metric option the same corrosion grade?

Yes. The metric machine screws are 316 stainless, marked A4, which is the same material designation. Corrosion resistance matches inch 316; only the thread standard differs.

Will small stainless screws gall?

Stainless can gall on stainless, and small sizes are easy to seize. Drive slowly, keep threads clean, and use a touch of anti-seize on tapped stainless. This prevents the cold-welding that ruins the threads.

Can I use these with stainless nuts?

Yes, 316 machine screws pair naturally with 316 nuts and washers for a consistent, corrosion-resistant joint. Matching the metal avoids galvanic mismatch and keeps the whole assembly marine rated.