Cap Nuts & Dome Nuts - Fasteners & Hardware

Cap Nuts & Dome Nuts

Dome and acorn nuts that cover the thread end, for safety and finish.

Cap nuts for two jobs: covering a protruding thread so nothing catches on it, and finishing a visible fixing. The dome is formed, not drilled, so the thread stays clean.

How we make it: Swiss CNC machining service →

M3–M20 metric±0.3 mm≥ 1.5× Ø rule6H -
Lead Time

3–5 weeks

Min Order

500 pieces

Certifications

ISO 9001:2015

Technical Specifications

ParameterValueUnit
Thread rangeM3–M20metric
Dome height±0.3mm
Thread depth≥ 1.5× Ørule
Thread class6H-
FinishPolished or plated-
StandardDIN 1587 / 917-

Available Materials

  • Stainless A2 / A4
  • Steel (zinc plated)
  • Brass
  • Aluminium
  • Nylon

Typical Applications

  • Handrails and balustrades
  • Furniture and fixture
  • Machine guards
  • Instrument cases
  • Marine hardware

Surface Finishes

  • Polished stainless
  • Zinc plating
  • Nickel plating
  • Brass natural
  • Anodise

Industries Served

  • Building Services
  • Consumer Products
  • Industrial Equipment
  • Marine
  • Instrumentation

What drives the price of this part

Derived from the callouts on this page. Where a driver is not on the drawing, it is not on this list.

Part size
Thread range at M3–M20 metric decides which machine the part lands on and how many setups it needs. Size is the driver buyers most often leave out of a first enquiry, and it is the one that changes the quote fastest.
Order size
Minimum order is 500 pieces, where setup and tooling are amortised across the batch and per-part cost settles around cycle time and material. Below that quantity the same part costs more per piece, not less.
Certification and paperwork
ISO 9001:2015. On a certified family the inspection and documentation work is part of the price: first article inspection, material traceability and the dimensional report are produced per order, not per sample.

See how cycle time is calculated in the machining time calculator and what else moves a price in the cost driver reference.

How these parts are inspected

Matched to the callouts above and the instruments actually on the floor.

  • Coordinate measuring machine (Zeiss CONTURA G2, two machines, GR&R 8.4% on the critical feature)
  • Dimensional report against the drawing, with a 100% check on critical features rather than a sample
  • Certificate of conformance and the mill certificate with every shipment
  • Thread gauges over the full thread range on the drawing

The full equipment list, with counts, is on the capability page; the inspection sequence is on quality and inspection.

Questions buyers ask

How much thread must be inside a cap nut?
About one and a half times the diameter, otherwise the load lands on the first threads only and they strip. Measure the protruding bolt before choosing the nut.

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