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Nuts · MS21055 and NASM25027 · Application guide

What Are Aerospace Corner Self-Locking Nutplates Used For?

Typical applications, the industries that specify aerospace corner self-locking nutplates, and how to choose the right size, material and finish for the joint.

Aerospace Corner Self-Locking Nutplates are used for fixed corner self-locking threads in aerospace panels. They are manufactured to MS21055 and NASM25027, and the choice of size, property class and finish is driven by the load in the joint and the environment it sits in.

Primary duty
Fixed corner self-locking threads in aerospace panels
Governing standard
MS21055 and NASM25027
Screw size range
632 to 1428
Category
Nuts

Application notes are general engineering guidance. Verify the property class and any approval requirement against your own design calculation.

What Are Aerospace Corner Self-Locking Nutplates Used For? application image

The primary duty of Aerospace Corner Self-Locking Nutplates is fixed corner self-locking threads in aerospace panels. Below: the sectors that specify them in volume, the checklist used to select the right size and material for the application, installation notes, and the known limits of the type. Stocked across roughly 632 to 1428, they cover heavy and structural work.

Typical Applications for Aerospace Corner Self-Locking Nutplates

The most common settings where these are specified:

  • Aircraft skin panels: corner-mounted self-locking nutplates in confined edges.
  • Aerospace equipment bays: fixed threaded points where a floating basket will not fit.
  • Avionics brackets: serviceable hardware mounted near a panel corner.
  • Transport interiors: compact self-locking threads behind trim.

How to Specify Aerospace Corner Self-Locking Nutplates for Your Application

  • Size: Match the nominal size to the mating thread or hole. This product spans 632–1428; 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 MS21055 and NASM25027. Quoting the standard on your order guarantees interchangeable dimensions between suppliers.

Installation & Assembly Practice

  • Run the nut down by hand before applying the wrench to catch cross-threading early.
  • Tighten the nut rather than the bolt head where access allows — the torque-to-preload relation is more consistent.
  • For locking styles, note that nyloc inserts are single-use in critical joints and lose grip above roughly 120 °C.

Common Selection Mistakes with Aerospace Corner Self-Locking Nutplates

  • Pairing a high-class bolt with a lower-class nut — the nut strips before the bolt reaches proof load; the nut class must meet or exceed the bolt class.
  • Using a plain nut with a spring washer in severe vibration instead of a prevailing-torque locking nut.
  • Re-using nyloc nuts in critical joints.

Where Aerospace Corner Self-Locking Nutplates 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.

Technical Drawing

Customize the parameters below — every spec field is editable, and the drawing redraws to match the values you choose. Changing the size will snap the other fields to that size's standard values; you can then override any individual value.

Sends the selected values to the quote form below.

Request a Quote

The form below follows the current technical drawing configuration. Change the drawing values above and the request details update automatically.

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Specification
Business Information

Dimensions & Specifications (MS21055 and NASM25027)

Thread sizeOverall length A (in)Mounting-hole spacing J (in)Width C (in)Nut height (in)Material optionsReference standard
6-320.6370.4860.3440.171cadmium-plated alloy steel or stainless steelMS21055 and NASM25027
8-320.637~0.8520.486~0.7070.344~0.5000.171~0.281cadmium-plated alloy steel or stainless steelMS21055 and NASM25027
10-320.637~0.8520.486~0.7070.344~0.5000.171~0.281cadmium-plated alloy steel or stainless steelMS21055 and NASM25027
1/4-280.637~0.8520.486~0.7070.344~0.5000.171~0.281cadmium-plated alloy steel or stainless steelMS21055 and NASM25027
Inside the plant

Manufactured in our own plant

This part is cold-formed, threaded, heat-treated and finished in-house. The stages below are where its class and finish are actually decided.

  1. Wire rod feeding into a cold heading machine
    01

    Cold heading

    Wire rod is drawn to size and cold-formed into blanks. Forming rather than cutting keeps the grain flow continuous around the head, which is where a bolt is most likely to fail.

    Head dimensions and under-head radius checked at set-up and per shift.

  2. Thread rolling machine producing bolt threads
    02

    Thread rolling

    Threads are rolled between hardened dies rather than cut. Rolled threads are stronger in fatigue than cut threads and hold pitch and flank angle far more consistently across a batch.

    Go / no-go ring gauges to ISO 965 tolerance class 6g.

  3. Baskets of bolts staged for heat treatment
    03

    Heat treatment

    Quench-and-temper brings carbon and alloy steel to the property class ordered — 8.8, 10.9 or 12.9 — with the furnace charge tracked so a finished lot can be traced back to it.

    Core hardness and tensile tested per lot to ISO 898-1.

  4. Zinc plated bolts in a treatment basket
    04

    Surface treatment

    Zinc, zinc-nickel, hot-dip galvanizing, black oxide, phosphate and Dacromet, selected against the service environment rather than against the price list.

    Coating thickness and neutral salt spray hours to ISO 9227.

Frequently Asked Questions

What are Aerospace Corner Self-Locking Nutplates used for?

Fixed corner self-locking threads in aerospace panels. They are supplied to MS21055 and NASM25027.

Which industries use Aerospace Corner Self-Locking Nutplates?

They are commonly specified in avionics brackets, transport interiors and aircraft skin panels, among other sectors.

How do I choose the right size of Aerospace Corner Self-Locking Nutplates?

Match the nominal size to the mating thread or hole. This product is available from 632 to 1428; the full dimension table on this page lists each size.

Do Aerospace Corner Self-Locking Nutplates need a locking feature?

If the joint sees vibration or cyclic load, use a locking style (nyloc, all-metal lock, or serrated flange) or a thread-locking adhesive. For static joints a standard nut tightened correctly is usually sufficient.

Can I get a quote for Aerospace Corner Self-Locking Nutplates in the size and material I need?

Yes. Use the technical drawing and quote form on this page to set the size and options, then send the exact configuration to our team for pricing and lead time.