Machine screws
Machine screws are a specialized subcategory within Tools & Fasteners (fastening accessories). Here you will find screws for robust, precise fastening applications on board and in everyday workshop use—for example, for fittings, electrical/electronic assemblies, mounts, equipment fastenings, and repairs. In the maritime environment, the following are particularly important: corrosion-resistant material, the correct thread standard, and clean installation to ensure that connections last.
Our product range (subject to availability) includes, among others, L’Ocean and Inox machine screws in standard sizes—often sold as a set with a nut (and, depending on the model, with washers). Brand names remain unchanged—important for consistent quality, material specifications, and reliable reordering.
Select the thread (e.g., M4/M5/M6), length, head/drive type, and material to suit the installation situation. This helps prevent stripped threads, contact corrosion, and unnecessary maintenance—especially in seawater, under vibrations, and with fluctuating temperatures.
- Dimensions & Standard: Select the thread (M…), length under head, head type (cylinder/countersunk), and drive (e.g., hex socket/Phillips) to match the component.
- Material & Corrosion Protection: For marine applications, stainless steel A4 (seawater-resistant) is often used—be mindful of material combinations to prevent galvanic corrosion.
- Installation & Securing: Washers/backing plates for load distribution, threadlocker if necessary, correct tightening torque, and protection against loosening due to vibration.
Examples from the product range: Inox cylinder head screw with nut (4 pcs.) M6 × 30 mm A4 stainless steel; Inox cylinder head screw with nut (6 pcs.) M4 × 30 mm A4 stainless steel; Inox cylinder head screw with nut (6 pcs.) M5 × 30 mm A4 stainless steel; L’Ocean stainless steel cylinder head screw + nut (4 pcs.) M6 × 60 mm A4 stainless steel.
FAQ
How do I find the right machine screw (M4/M5/M6, length, head)?
The key factors are thread diameter (e.g., M4/M5/M6), length (measured below the head), and the head/drive type. Cylinder head screws are often used when a clean fit and good force transmission through the head are required; countersunk heads are used when the screw needs to sit flush. Tip: Measure the material thickness(es) plus washers and allow for sufficient thread engagement in the nut/thread.
A2 or A4 – which is best for onboard use?
For seawater and outdoor applications, A4 stainless steel is usually the safer choice because it offers better corrosion resistance in salty environments. A2 can work in less aggressive environments but is often more susceptible to corrosion under prolonged exposure to salt and moisture. Important: Material mixing (e.g., stainless steel on aluminum) can promote contact corrosion—insulation, suitable paste/separator, and clean assembly help here.
What “compatibility” factors are truly important for machine screws?
This primarily refers to the thread standard (metric M… vs. inch/UNC/UNF), the pitch (standard/fine thread), the head geometry (flat/countersunk), and the mating part (nut, threaded insert, threaded hole). For repairs, adopting the existing standard exactly is usually the quickest solution.
Assembly: What to consider (load distribution, loosening, sealing)?
For permanent connections: Use washers for load distribution; for thin laminates, use backing plates if necessary. Self-locking nuts or suitable threadlocker (depending on the application) help prevent loosening. For through-holes in the deck/hull: Deburr the hole cleanly and use a suitable sealant to prevent water from penetrating the core material or structure.
How do I prevent contact corrosion (stainless steel/aluminum) and “seizing”?
Contact corrosion can occur when stainless steel is in contact with aluminum or in very humid environments. Use insulating washers, release agents/pastes (suitable for marine applications), and ensure that mounting surfaces are clean and dry. To prevent “galling” with stainless steel, use a suitable assembly paste and apply the correct torque—do not overtighten.
How can I ensure the screw connection remains reliable over the long term?
Perform regular visual inspections (for corrosion, loose nuts, play), especially after the first few trips or after severe vibrations/stresses. Rinse off salt and dirt, retighten critical connections (if applicable), and replace damaged screws/nuts promptly. This ensures that fittings and mounts remain safe over the long term.
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