Marine CNC Machined Parts
Marine-grade materials: 316L & duplex stainless steel, 5083/6061 aluminum, titanium, copper-nickel and aluminum bronze
CNC turning, milling, 5-axis machining, Swiss CNC and grinding
±0.01 mm tolerances on shafts, housings, valve and pump components
Material certificates and inspection reports available on request
We manufacture custom marine CNC machined parts from customer drawings and CAD files, including propeller shafts, shaft sleeves, rudder components, valve bodies, pump housings and impellers, flanges, pipe fittings, manifolds, housings for ROV and subsea equipment, deck hardware and marine fasteners. Our CNC turning, milling, 5-axis machining, Swiss CNC and turn-mill capabilities support tight-tolerance components for shipbuilding, offshore installations, seawater systems, marine engines and subsea equipment.
CNC Machined Parts for Marine Applications
Marine equipment operates in one of the most demanding environments in industry: continuous exposure to seawater, high loads, vibration and temperature extremes. We machine components for the systems listed below, selecting materials and surface protection according to the service environment of each part.
Shipbuilding & Propulsion
Propeller shafts · stern tube sleeves · rudder stocks and pintles · shaft couplings · bearing housings · deck fittings
Materials: 316L · 17-4 PH · 4140 · 4340 · 5083
Marine Engines & Power Systems
Engine shafts · housings · pistons and liners · turbocharger components · fuel system fittings · bearing housings
Materials: 4140 · 4340 · 316L · 17-4 PH · Inconel 718
Seawater Systems & Pumps
Pump housings · impellers · valve bodies · strainer components · sea chest fittings · heat exchanger parts · desalination components
Materials: C95800 aluminum bronze · 316L · duplex 2205 · titanium · copper-nickel
Offshore Oil & Gas
Subsea connector housings · manifold components · wellhead parts · choke and valve trim · BOP components
Materials: duplex 2507 · Inconel 625 · 17-4 PH · titanium
ROV & Subsea Equipment
Pressure housings · frames and skids · thruster components · manipulator arms · camera and sensor housings · connector bodies
Materials: 6061-T6 · 7075-T6 · 316L · titanium · Inconel
Marine Hardware & Deck Equipment
Winch components · fairleads · cleats · hinges · latches · ladder and railing fittings
Materials: 316L · 5083 · C46400 naval brass
send your drawing or CAD file for material and machining review
Marine CNC Machined Parts We Manufacture
Propeller Shafts & Tail Shafts
High-precision shafting with controlled journal diameters, runout, keyways and coupling fits.
Materials: 4140 · 4340 · 17-4 PH · 316L · duplex 2205
Shaft Sleeves & Liners
Corrosion and wear protection for stern tubes, intermediate shafts and sealing areas.
Materials: 316L · duplex 2205 · C95800
Valve Bodies & Trim
For seawater ball, butterfly, gate and control valves in piping and fire systems.
Materials: C95800 · 316L · duplex 2205/2507
Pump Housings & Impellers
Centrifugal and positive-displacement pumps for seawater, bilge, ballast and fire systems.
Materials: C95800 · 316L · duplex · titanium
Flanges & Pipe Fittings
Flanges, reducers, tees and threaded fittings for marine piping systems.
Materials: 316L · 316 · duplex · carbon steel
Fittings & Adapters
Hydraulic and pneumatic fittings for steering, winch, thruster and control systems.
Materials: 316L · C36000 · C46400
Hydraulic Manifolds
Manifold blocks for steering, stabilizer, winch and thruster hydraulics.
Materials: 6061-T6 · 316L · 4140
Housings & Enclosures
Machined housings for sensors, electronics, cameras and deck equipment.
Materials: 6061-T6 · 7075-T6 · 316L · titanium
CNC Turning
Best for: Shafts · sleeves · valve stems · fittings · flanges
Ideal for cylindrical marine components and rotating parts.
CNC Milling
Best for: Housings · manifolds · brackets · mounting plates
Suitable for flat, prismatic and multi-feature components.
5-Axis CNC Machining
Best for: Complex impellers · subsea housings · valve bodies · manifolds
Machines complex geometries and compound angles in one setup.
CNC Turn-Milling
Best for: Drive shafts · couplings · rotary components with milled features
Combines turning and milling for complex rotational parts.
Swiss CNC Machining
Best for: Small fittings · fasteners · sensor components
Designed for small, slender and high-volume precision components.
CNC Grinding
Best for: Shaft journals · bearing seats · sealing surfaces
Used for critical diameters, fits and smooth functional surfaces (Ra 0.2–0.4 μm achievable).
Marine CNC Machining Materials
For marine components, material selection depends on seawater exposure, pressure, load, galvanic coupling, wear and service temperature. We machine a range of metal materials for shafts, pumps, valves, fittings, housings and structural components.
| Material | Common Grades | Typical Marine Applications | Key Advantages |
|---|---|---|---|
| Stainless Steel | 304 · 316 · 316L · 17-4 PH | Fittings, fasteners, valve parts, deck hardware | Good corrosion resistance; 316L preferred in chloride service |
| Duplex & Super Duplex | 2205 · 2507 | Seawater pumps, valves, subsea components | High strength with resistance to pitting and stress corrosion |
| Aluminum | 5083 · 6061-T6 · 7075-T6 | Housings, ROV frames, deck fittings, lightweight structures | Lightweight, anodizable, marine-grade options |
| Titanium | Grade 2 · Grade 5 (Ti-6Al-4V) | Seawater valves, heat exchanger parts, shafts, ROV components | Outstanding seawater corrosion resistance, high strength-to-weight |
| Copper-Nickel | C70600 · C71500 | Heat exchanger parts, seawater piping fittings | Biofouling resistance and corrosion resistance in seawater |
| Aluminum Bronze & Naval Brass | C95800 · C46400 | Pump impellers, valve bodies, propeller components, wear parts | Cavitation and erosion resistance, seawater compatibility |
| Carbon & Alloy Steel | 1045 · 4140 · 4340 | Shafts, rudder stocks, high-load components | High strength; requires protective coating in seawater service |
| Nickel Alloys | Inconel 625/718 · Monel K500 | Subsea components, high-temperature and corrosion-critical parts | Extreme corrosion resistance and high strength |
Material Selection for Seawater Environments
Seawater is one of the most corrosive fluids in industry. When we review a marine part drawing, we look at four factors that determine whether a component will survive in service:
Corrosion Resistance
Chlorides attack most metals through pitting and crevice corrosion. 316L resists mild seawater service; duplex 2205/2507 and titanium are selected for pumps, valves and subsea parts in full seawater contact.
01
Galvanic Compatibility
Dissimilar metals coupled in seawater accelerate corrosion of the less noble material. We review material pairing in multi-part assemblies and recommend compatible grades or insulating measures.
02
Erosion & Cavitation
Pump impellers, propellers and valve trim face erosion and cavitation damage. Aluminum bronze C95800, duplex stainless and titanium resist these wear mechanisms.
03
Weight & Strength
ROV and subsea structures need strength without weight: titanium and 7075-T6 aluminum are common. Shafting and high-load parts use 17-4 PH, duplex and alloy steels.
04
Marine CNC Machining Tolerances & Specifications
| Specification | Typical Capability | Typical Marine Applications |
|---|---|---|
| Linear Dimensions | ±0.01 mm | Housings, flanges, manifolds |
| Shaft Diameter | ±0.01–0.02 mm | Propeller shafts, journals, sleeves |
| Bore Diameter | ±0.01 mm | Pump housings, bearing bores, valve bodies |
| Concentricity / Runout | Down to 0.02 mm | Rotating shafts, couplings, journals |
| Keyway Width & Position | ±0.05 mm | Shafts and couplings |
| Flatness | Down to 0.02 mm/100 mm | Flanges, mounting faces |
| Surface Roughness | Ra 0.8–3.2 μm (down to Ra 0.2–0.4 μm) | Sealing faces, shaft journals, bearing seats |
| Thread Tolerance | According to ISO / ASME requirements | Threaded fittings, flanges and fasteners |
Critical Features We Control
Shaft & Bearing Fits - controlled diameters for bearings, sleeves, couplings and glands.
Concentricity & Runout - important for propeller shafts and rotating components.
Bore & Housing Fits - accurate bores for pump casings, valve bodies and bearing seats.
Sealing Surfaces - controlled roughness and flatness for gaskets, O-rings and mechanical seals.
Keyways & Splines - accurate width, position and fit for torque transmission.
Surface Finishes for Marine CNC Parts
As Machined
Bead Blasting
Polishing
Hard Anodizing
Black Oxide
Zinc Plating
Nickel Plating
Powder Coating
| Surface Finish | Applicable Materials | Typical Marine Parts | Main Benefit |
|---|---|---|---|
| Passivation | 316 · 316L · 17-4 PH | Fittings, fasteners, valve components | Removes free iron, improves pitting resistance |
| Electropolishing | 316L | Shafts, pump internals | Smooth, clean surface; improves corrosion resistance |
| Anodizing | 6061-T6 · 5083 | Housings, brackets, deck fittings | Corrosion resistance, wear resistance, color options |
| Hard Anodizing | 6061-T6 · 7075-T6 | ROV housings, wear surfaces | Hard, wear-resistant protective layer |
| Electroless Nickel Plating | 4140 · 1045 · Aluminum | Shafts, hydraulic components | Uniform wear and corrosion protection |
| Zinc Plating | Carbon steel | Interior fasteners and brackets | Economical protection for interior service |
| Hot-Dip Galvanizing | Carbon steel | Structural brackets, deck hardware | Heavy-duty corrosion protection |
| Powder Coating | Aluminum · Steel | Housings, deck equipment | Durable protective coating |
| Bead Blasting | Aluminum · Stainless · Steel | Housings, covers | Uniform matte finish |
| PTFE / Xylan Coating | Steel · Stainless | Bolts, sliding components | Low friction and corrosion protection |
Marine CNC Machining Quality Control
Material Verification
Material Verification
Dimensional Inspection
GD&T Inspection
Thread Inspection
Surface Finish Inspection
Final Inspection
Packaging Inspection
We inspect critical dimensions, fits, runout and surface requirements throughout production to ensure CNC machined marine parts meet the drawing. For projects that require classification-society or class-survey documentation, we can supply material certificates and inspection records to support your documentation package.
| Inspection Item | Equipment / Method | Typical Marine Parts |
|---|---|---|
| Dimensional Inspection | CMM · Calipers · Micrometers | Overall part dimensions |
| Shaft Diameter | Micrometer · CMM | Propeller shafts, journals, sleeves |
| Bore Diameter | Bore Gauge · Pin Gauge · CMM | Pump housings, bearing bores |
| Concentricity & Runout | CMM · Dial Indicator | Rotating shafts, couplings |
| Keyway / Spline | Go/No-Go Gauges · CMM | Shafts and couplings |
| Thread Inspection | Go/No-Go Thread Gauges | Threaded fittings and fasteners |
| Surface Roughness | Roughness Tester | Sealing faces, bearing seats |
| Material Verification | Spectrometer + Material Certificate | Incoming raw material (EN 10204 3.1 available) |
| NDT (on request) | Dye Penetrant Testing | Shafts and critical components |
| Final Inspection | CMM + Inspection Report | Final dimensional acceptance |
Need documented quality control? Send us your drawings and inspection requirements.
Prototype & Low-Volume CNC Machining for Marine
Marine projects often start with prototypes - new shafting designs, pump development, ROV components or retrofit parts that must be tested before full-scale production. We support prototype and low-volume CNC machining from initial samples to repeat small-batch orders.
Prototype Machining
For new equipment, pump and valve development, and design validation.
Typical Quantity: 1–10 pcs
Low-Volume Production
For sea trials, pilot systems and initial production runs.
Typical Quantity: 10–1,000+ pcs
Repeat Production
For spare parts and recurring orders with established designs.
Typical Quantity: Based on project requirements
Suitable for
Propeller shafting and stern tube components
Pump and valve development
ROV and subsea equipment
Engine and power-system parts
Deck hardware and fittings
Spare parts and retrofits for existing vessels
Packaging & Lead Time for Marine CNC Parts
Packaging
Individual Protection: PE bags, foam, or protective film for machined surfaces
Corrosion Protection: VCI paper and oiling for steel parts in overseas transit
Small Parts: Partitioned cartons to prevent scratching and part-to-part contact
Precision Parts: Foam inserts and separate compartments for critical components
Heavy Parts: Reinforced cartons or export-grade wooden cases
Custom Packaging: Part numbers, labels, quantities, and customer-specific packing requirements
Typical Lead Time
| Order Type | Typical Lead Time |
|---|---|
| Prototype | 5–10 working days |
| Low-Volume Order | 10–20 working days |
| Production Order | 15–30 working days |
| Repeat Order | 10–25 working days |
FAQ
Q: 1. What marine CNC machined parts can you manufacture?
A: We manufacture custom propeller shafts, shaft sleeves, rudder components, valve bodies, pump housings and impellers, flanges, pipe fittings, manifolds, ROV and subsea housings, deck hardware and fasteners for marine applications.
Q: 2. What materials do you machine for marine applications?
A: We machine 316 and 316L stainless steel, duplex 2205 and super duplex 2507, 17-4 PH, 5083/6061/7075 aluminum, titanium Grade 2 and Grade 5, copper-nickel C70600/C71500, aluminum bronze C95800, naval brass C46400, carbon and alloy steel, and nickel alloys such as Inconel 625/718.
Q: 3. What CNC machining tolerances can you achieve?
A: Our standard CNC tolerance is typically ±0.05 mm, with precision machining down to ±0.02 mm and selected critical features to ±0.01 mm, depending on geometry, material and drawing requirements.
Q: 4. Can you machine propeller shafts and stern tube components?
A: Yes. We machine shafts, sleeves and liners with controlled diameter, runout, keyways and bearing-fit dimensions, in alloy steel, 17-4 PH, 316L and duplex grades.
Q: 5. Can you machine parts for seawater pumps and valves?
A: Yes. We machine pump housings, impellers, valve bodies and trim from aluminum bronze C95800, 316L, duplex stainless and titanium, which resist seawater corrosion, erosion and cavitation.
Q: 6. Do you machine ROV and subsea equipment components?
A: Yes. We machine pressure housings, frames, thruster components, manipulator parts, camera and sensor housings from aluminum, stainless, titanium and nickel alloys.
Q: 7. Can you supply material certificates and inspection reports?
A: Yes. Depending on project requirements, we can provide material certificates (EN 10204 3.1), dimensional inspection reports, CMM reports and surface finish records to support your documentation package.
Q: 8. What surface finishes protect parts against seawater corrosion?
A: Depending on material and application, we offer passivation, electropolishing, anodizing, hard anodizing, electroless nickel plating, zinc plating, hot-dip galvanizing, powder coating and PTFE coating.
Q: 9. How do you handle galvanic corrosion between different materials?
A: We review material pairing in multi-part assemblies and recommend compatible grades, insulating measures or coatings to prevent accelerated corrosion in seawater service.
Q: 10. Can you machine bronze and copper-nickel alloys?
A: Yes. We machine aluminum bronze C95800, naval brass C46400, and copper-nickel C70600/C71500 for pump, valve, propeller and heat exchanger components.
Q: 11. Do you accept 2D drawings and CAD files?
A: We can work from common STEP, STP, IGES, IGS, SolidWorks, DXF and 2D drawing files.
Q: 12. Do you support prototype and low-volume production?
A: Yes. We support prototype quantities from 1–10 pieces, low-volume production from 10–1,000+ pieces, as well as repeat production orders.
Q: 13. What is the typical lead time for marine CNC parts?
A: Typical lead times are 5–10 working days for prototypes, 10–20 working days for low-volume orders, and 15–30 working days for production orders, depending on part complexity, quantity, material and finishing.
Send your 2D drawing or 3D CAD file, material grade, quantity, tolerance and finishing requirements
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