Cap (Acorn) Nuts are used primarily for exposed, hand-contact or decorative joints where the protruding thread must be covered. This page summarizes where they fit, the industries that rely on them, and the practical points to get right when you specify them — to DIN 1587. Stocked across roughly M4 to M20, they cover general to heavy-duty work.
Typical Applications for Cap (Acorn) Nuts
The most common settings where these are specified:
- Frames & weldments: captive or welded options for repeatable assembly.
- Exposed assemblies: handrails, furniture and equipment people touch.
- Sanitary & decorative: covering the thread end for a clean, safe finish.
- General machine building: fastening covers, brackets, motors and sub-assemblies on production equipment.
- Maintenance & repair (MRO): a stocked size for servicing existing plant where the original fastener spec must be matched.
How to Specify Cap (Acorn) Nuts for Your Application
- Size: Match the nominal size to the mating thread or hole. This product spans M4–M20; check the full table below for the exact dimensions of each size.
- Locking & grade: Match the strength grade to the bolt, and choose a locking style (nyloc, all-metal, serrated flange) if the joint sees vibration.
- Environment: For damp, coastal or chemical exposure prefer A4/316 stainless or a suitable coating; indoors, plated steel or A2 is usually sufficient.
- Standard: This product is supplied to DIN 1587. Quoting the standard on your order guarantees interchangeable dimensions between suppliers.
Where Cap (Acorn) Nuts Are Not the Right Choice
Not on their own — they need a matching bolt or stud — and a plain nut is not a substitute for a locking type under heavy vibration.