Products

Cap Nut (Acorn Nut / Dome Nut) – Decorative & Protective Thread Cover

The Cap Nut (Acorn Nut / Dome Nut) is a specialized hexagonal fastener featuring a domed, closed-end top that completely covers the exposed end of a bolt or threaded stud. This unique design serves multiple critical functions: it protects threads from moisture, dirt, and corrosion; provides a smooth, aesthetically finished appearance; prevents accidental injuries from sharp or protruding threads; and helps prevent tampering. At Malaxy, we manufacture high-precision cap nuts in a full range of materials, strength grades, and surface finishes to meet the demanding requirements of automotive, machinery, construction, furniture, and architectural applications.

✔ Fully enclosed domed top covers and protects exposed threads
✔ Provides clean, finished appearance for visible fastening points
✔ Prevents thread damage from moisture, debris, and corrosion
✔ Reduces risk of injury from sharp bolt ends
✔ Available in metric (DIN 1587) and inch (ASME B18.6.3) standards

Key Features & Advantages

• Full Thread Protection – The closed-end dome completely encloses the bolt end, shielding it from moisture, dust, dirt, and corrosive elements, significantly extending the service life of threaded connections.

• Aesthetic Finish – Provides a smooth, polished, and professional appearance, ideal for visible or decorative fastening applications where appearance matters.

• Safety Enhancement – The smooth domed top eliminates sharp or protruding thread ends, preventing accidental injuries to personnel handling or working around equipment.

• Corrosion Resistance Options – Available in stainless steel (304/316) for marine, outdoor, and chemical environments, as well as various plated finishes for standard applications.

• Tamper Deterrence – The enclosed design makes it more difficult to access the bolt end, providing a basic level of tamper resistance.

• Two Profile Options – High crown (standard) for extended thread coverage and greater protection, low crown for confined spaces and lower profile applications.

• Vibration Resistance – Available with nylon insert (DIN 986) for prevailing torque locking in high-vibration environments.

Material & Grade Options

Surface Finishes Available:

• Zinc plating (clear, yellow, black) – standard corrosion protection

• Hot-dip galvanizing – heavy-duty outdoor use

• Chrome plating – bright decorative finish

• Nickel plating – corrosion-resistant decorative finish

• Black oxide + oil – minimal thickness, industrial appearance

• Dacromet® / Geomet® – high salt spray resistance (up to 1000h)

• Xylan® / PTFE / Teflon® – low friction, chemical resistance

• Phosphate & oil – temporary rust protection

⚙️ Quality Standards & Certifications

Our cap nuts are manufactured and tested in compliance with:

• DIN 1587 – Hexagon domed cap nuts, high type, product grades A and B (metric, M4–M24)

• DIN 917 – Hexagon cap nuts, low type (low crown)

• DIN 986 – Hexagon domed cap nuts with non-metallic insert (prevailing torque)

• ASME B18.6.3 – American standard for hex cap nuts (inch series, UNC/UNF)

• ANSI/ASME B18.2.2 – American standard for nuts (referenced for general nut specifications)

• GB/T 923 – Chinese national standard for cap nuts

• IFI 111 – Industrial Fasteners Institute standard for hex cap nuts

• RoHS, REACH – Environmental compliance

Quality Control Includes:
✔ 100% thread gauging (on critical orders)
✔ Proof load testing per applicable standards
✔ Hardness testing (HRC or HV as applicable)
✔ Salt spray test for coating verification
✔ Dimensional inspection per standard drawings
✔ Visual inspection for surface defects and finish quality

Industry Applications

• Automotive – Engine compartment fasteners, decorative wheel covers, exposed chassis bolts, seat mounting hardware, axle assemblies, tire and wheel fastening

• Heavy Machinery & Industrial Equipment – Machine guards, safety covers, exposed threaded rods on equipment, conveyor systems, hydraulic cylinder ends

• Construction Equipment – Scaffolding connections, guardrail fasteners, exposed bolts on heavy equipment, tower crane assemblies

• Furniture & Cabinetry – Visible fastening points requiring a finished appearance, office furniture, shelving systems, storage cabinets

• Architectural & Decorative – Railings, handrails, signage, display fixtures, exposed structural connections where aesthetics matter

• Marine & Offshore – Boat deck hardware, marine railings, dock equipment, offshore platform exposed connections (316 stainless steel recommended)

• Food Processing & Medical – Equipment requiring smooth, sanitary surfaces with no exposed thread ends, easy-clean applications

• Electrical & Electronics – Panel fastening, equipment housings, terminal connections (brass for conductivity)

OEM & Customization Services

As a leading fastener manufacturer based in Shanghai, Malaxy offers comprehensive customization for cap nuts:

• Custom thread sizes – Fine pitch (e.g., M10×1.25), UNF, UNJC, left-hand thread, custom pitches

• Profile options – High crown (standard DIN 1587), low crown (DIN 917), extra-high for extended stud protection

• Non-standard dimensions – Custom heights, across-flats dimensions, and diameters

• Material selection – Carbon steel, stainless steel (304/316), alloy steel, brass, bronze, titanium

• Special coatings – Xylan®, PTFE, Teflon®, zinc-nickel alloy, chrome, nickel, silver, copper, tin plating

• Locking feature – Nylon insert (prevailing torque) per DIN 986

• Packaging – Bulk in cartons, small poly bags, boxes with labels, private labeling, or custom kitting

Our strategic location at Shanghai port ensures fast, economical shipping worldwide with full batch traceability.

✅ Request a quote for Cap Nut (Acorn Nut / Dome Nut) today – Standard sizes in stock, custom orders delivered in 2–4 weeks!