Cap Nuts (also called dome nuts, acorn nuts, or mushroom nuts) are cylindrical nuts with a rounded or domed top that covers and protects the exposed thread of a bolt or stud. They combine functional protection against corrosion and damage with a clean, decorative appearance, making them popular in automotive, furniture, and architectural applications. Manufactured from carbon steel (zinc-plated), stainless steel (304/316), or brass/nylon, they offer both durability and aesthetic appeal.
- Material:
- Carbon Steel (Grade 4.8/8.8, zinc-plated, black oxide, or painted).
- Stainless Steel (304/316, passivated for corrosion resistance).
- Brass: For decorative finishes (polished or lacquered).
- Nylon/Plastic: Lightweight, non-conductive, and ideal for non-marring applications.
- Size Range:
- Metric: M3–M24 (ISO 4034, DIN 1587).
- Imperial: #4–1" (UNC/UNF, ASME B18.2.2).
- Design Types:
- Standard Dome: Smooth, rounded top (most common).
- Flanged Dome: Extended base for increased surface area (reduces torque stress).
- Knurled Dome: Textured sides for improved grip during hand tightening.
- Finish:
- Zinc plating (silver/blue/yellow), powder coating (custom colors), or passivation (stainless steel).
- Standard Carbon Steel/Zinc-Plated: 5,000 pieces (common sizes like M8/M10 in stock).
- Stainless Steel/Brass/Plastic: 2,000 pieces (e.g., 316 stainless or brass decorative caps).
Factory Advantages: ISO-certified production, precision threading (tolerance: ±0.05mm), support for custom dome profiles and non-standard thread lengths, with lead times of 10–20 days for bulk orders.
- Automotive/Aerospace: Concealing bolts on engine covers, trim panels, and exterior components.
- Furniture & Architecture: Securing table legs, handrails, and decorative fixtures (brass caps for vintage designs).
- Electronics/Instrumentation: Protecting exposed threads in control panels and equipment enclosures.
- Industrial Machinery: Preventing debris accumulation and corrosion on moving parts.
- Thread Protection: Fully covers bolt ends to prevent snagging, rust, or damage from impacts.
- Aesthetic Appeal: Polished brass or colored powder-coated finishes for decorative applications.
- Corrosion Resistance:
- 316 stainless steel (1,000+ hours salt spray) for marine environments.
- Nylon caps (UV-stabilized) for outdoor use without metal-on-metal contact.
- Torque Compatibility: Standard hexagon drive for wrench tightening; knurled designs for hand adjustment.
- Non-Standard Sizes: Extra-long caps for thick materials or micro caps (M3) for precision equipment.
- Special Finishes: Chrome plating, PVD (titanium nitride for hardness), or anodized aluminum (color options).
- Logo Embossing: Custom branding on the dome surface for OEM projects.
Contact Us
Request a quote for cap nuts tailored to your needs! Factory-direct pricing and quick turnaround for protective, decorative, or industrial fastener solutions.
JH Bolt Co., Ltd is a professional manufacturer of different types of bolts with more than 15 years rich manufacturer experience. The factory area is more than 1500 squares with more than hundreds different types ofnevproduction machines. There are more than 50 people who work here for at least 5 years.With quality &customer frst, staffs second, then company, Our products are widely recog-nized and trusted by users all over the world. Proft for the development of communication, We are here for you 12 hours a day, 7 days a week!
