Skip to content
WhatsApp
Request a Quote
Nuts · MS21059 and NASM25027 · Application guide

What Are Aerospace Two-Lug Floating Self-Locking Nutplates Used For?

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

Aerospace Two-Lug Floating Self-Locking Nutplates are used for floating self-locking threads that absorb aerospace panel tolerance. They are manufactured to MS21059 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
Floating self-locking threads that absorb aerospace panel tolerance
Governing standard
MS21059 and NASM25027
Screw size range
440 to 51624
Category
Nuts

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

What Are Aerospace Two-Lug Floating Self-Locking Nutplates Used For? application image

Aerospace Two-Lug Floating Self-Locking Nutplates are selected when an assembly calls for floating self-locking threads that absorb aerospace panel tolerance. This application guide to the MS21059 and NASM25027 type covers concrete end-uses, the specification checklist, correct installation, and where an alternative fastener performs better. Stocked across roughly 440 to 51624, they cover heavy and structural work.

Typical Applications for Aerospace Two-Lug Floating Self-Locking Nutplates

The most common settings where these are specified:

  • Aerospace access panels: two-lug floating nutplates that absorb hole-position tolerance.
  • Aircraft interiors: removable trim panels with many closely spaced fixings.
  • Avionics enclosures: self-locking captive threads behind a finished panel.
  • Motorsport bodywork: lightweight panels removed without losing the nut.

How to Specify Aerospace Two-Lug Floating Self-Locking Nutplates for Your Application

  • Size: Match the nominal size to the mating thread or hole. This product spans 440–51624; 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 MS21059 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 Two-Lug Floating 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 Two-Lug Floating 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.

Request a Quotation

Specification
Business Information

Dimensions & Specifications (MS21059 and NASM25027)

Thread sizeOverall length A (in)Width B (in)Mounting-hole spacing J (in)Nut height (in)Material optionsReference standard
4-400.9480.4160.6880.175cadmium-plated alloy steel or stainless steelMS21059 and NASM25027
6-320.948~1.2920.416~0.6800.688~1.0000.175~0.344cadmium-plated alloy steel or stainless steelMS21059 and NASM25027
8-320.948~1.2920.416~0.6800.688~1.0000.175~0.344cadmium-plated alloy steel or stainless steelMS21059 and NASM25027
10-320.948~1.2920.416~0.6800.688~1.0000.175~0.344cadmium-plated alloy steel or stainless steelMS21059 and NASM25027
1/4-280.948~1.2920.416~0.6800.688~1.0000.175~0.344cadmium-plated alloy steel or stainless steelMS21059 and NASM25027
5/16-240.948~1.2920.416~0.6800.688~1.0000.175~0.344cadmium-plated alloy steel or stainless steelMS21059 and NASM25027
3/8-240.948~1.2920.416~0.6800.688~1.0000.175~0.344cadmium-plated alloy steel or stainless steelMS21059 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

How do I choose the right size of Aerospace Two-Lug Floating Self-Locking Nutplates?

Match the nominal size to the mating thread or hole. This product is available from 440 to 51624; the full dimension table on this page lists each size.

Do Aerospace Two-Lug Floating 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.

What material should Aerospace Two-Lug Floating Self-Locking Nutplates be for outdoor use?

For damp, coastal or chemical environments specify A4 (316) stainless or a suitably coated steel. For indoor or dry use, A2 (304) stainless or zinc-plated steel is normally adequate.

Are Aerospace Two-Lug Floating Self-Locking Nutplates made to a recognized standard?

Yes — they are manufactured to MS21059 and NASM25027, so dimensions are interchangeable between suppliers when you quote the standard on your order.

Can I get a quote for Aerospace Two-Lug Floating 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.