High Crown Cap Nuts
What are High Crown Cap Nuts?
High crown cap nuts—also called high crown dome or high crown acorn nuts—are hex nuts with an extended domed top. The taller crown gives extra internal clearance so the nut can cover longer stud projections, protecting exposed threads while delivering a clean, decorative finish.
Why choose High Crown Cap Nuts?
- Extra coverage – deeper internal dome hides longer bolt ends that would bottom out in a standard cap nut.
- Safety & protection – smooth, closed end removes sharp edges and shields threads from damage and debris.
- Upgraded appearance – taller crown provides a distinctive, finished look for visible hardware.
- Easy install – fits standard wrench or socket; no special tools required.
Materials & finishes
- 18-8 / 304 Stainless Steel – reliable general-purpose corrosion resistance for indoor/outdoor use.
- 316 Stainless Steel – higher resistance for coastal, marine, and chloride exposure (when available).
- Plated Carbon Steel – bright chrome-like finishes for indoor environments and show pieces.
Common uses for High Crown Cap Nuts
- Furniture, cabinetry, and decorative fasteners where hardware is visible
- Automotive, motorcycle, and bicycle finishing hardware
- Architectural metalwork, guards, and hand-contact areas
- Displays, fixtures, and equipment panels needing a polished look
How to size and select High Crown Cap Nuts
Match the nut to your fastener’s diameter and thread (e.g., 1/4-20, 3/8-16, M6-1.0, M8-1.25). Choose high crown when the stud projects too far for a standard cap nut and would bottom inside the dome. For very long projections or when even more room is needed, consider extra-tall styles. Select material to suit the service environment and desired appearance.
Installation tips for High Crown Cap Nuts
- Start threads by hand to avoid cross-threading; tighten with a correctly sized wrench or socket.
- Confirm the stud does not bottom inside the dome before the joint is tight; step up crown height if needed.
- Use a flat washer to protect finished surfaces and spread load; add a lock washer or jam nut for vibration resistance when specified.
- Keep materials compatible (e.g., stainless nut with stainless bolt) to reduce galvanic corrosion outdoors.
High Crown Cap Nuts FAQs
Use the accordion below for answers about crown height, sizing, materials, and best practices for high crown dome (acorn) nuts.
High crown has a taller, deeper dome to cover longer stud projections. Standard has the lowest dome and least internal clearance.
Choose high crown when a standard dome bottoms out but you only need a modest increase in internal depth. Use extra-tall for even longer projections.
Match the nut to your fastener’s nominal size and thread pitch (e.g., 3/8-16 UNC, M8-1.25). If the stud still contacts the inside of the dome before clamp is achieved, step up to a taller crown.
Yes, use 304 stainless for general outdoor exposure; use 316 stainless for coastal, marine, or chloride environments.
They’re primarily used for thread protection and appearance. Follow specified nut grade/class for structural joints.
Yes. A flat washer helps protect surfaces and distribute load; add a lock washer or jam nut if vibration resistance is required.
Check available clearance around the nut; the extended crown increases overall height compared with standard cap nuts.
Generally yes, if threads are undamaged and the dome has not been deformed or bottomed during previous installation.
Plated carbon steel provides a bright, show finish for indoor settings; stainless delivers a modern look with corrosion resistance.
Use torque values appropriate for the bolt size/grade and lubrication. Stop if you feel the stud bottom inside the dome.