Shop verification card
Self-locking nutplates (MS21047, MS21059, MS21069, MS21078; rivetless ForceTec)
generic-NAS · Nutplate · MS21047[-|L][dash][K] · e.g. MS21047L4K (.250-28, dry film lubricant, countersunk or dimpled rivet holes) · NASM21047 same PIN
speclok.com
10/1/2026
Install sequence
Before you install
- Sizes offered: .086-56 (MS21069 -02) and .112-40 UNJC-3B to .625-18 UNJF-3B (MS21047F Table I)
- Tool: Riveted: nutplate drill (two holes at once) and rivets per the design; rivetless ForceTec: FTI mandrel, split sleeve and puller
- Standard shop tooling.
- Training: Not stated in the cited documents.
- Lead-time risk: Medium
Installed preload
Not published for the nutplate. MIL-DTL-25027H sets locking, breakaway, torque-out and push-out values for the nut (see datasheet strength).
Gauge kit (published part numbers)
| Gauge | Sizes | Checks / limits | Source |
|---|---|---|---|
| Figure 3 functional alignment gage | all | Plate nut functional alignment gage | MIL-DTL-25027H (self-locking nuts), p.9, 31, 4.5.1.2; Figure 3 |
Removal
No published removal procedure found; follow the manufacturer's instructions. Steps: speclok.com/tooling/nutplate#removal
Accept / reject after install
- "BOLTS, STUDS OR SCREWS MUST EXTEND THRU THE SELF-LOCKING NUT FOR A MINIMUM LENGTH EQUIVALENT TO TWO THREADED PITCHES. THIS LENGTH INCLUDES THE CHAMFER." (MS33588E req. 2)
- "SELF-LOCKING PLATE NUTS SHALL BE ATTACHED TO THE STRUCTURE IN A POSITIVE MANNER ... THE MANNER OF ATTACHMENT SHALL PERMIT REMOVAL WITHOUT DAMAGE TO THE STRUCTURE AND PERMIT REPLACEMENT OF THE NUTS." (MS33588E req. 3)
- Rivet holes: MS21047F Table I gives øK (+.005 -.000) .098 at -04 to -4, .130 at -5 and -6, .161 at -7 to -10; "DIMPLED RIVET HOLE TOLERANCE FOR øK IS +.015 -.000" (footnote 3/); countersink or dimple 100° ±2°.
- "In the case of plate nuts, if proper bolt grip length is not available, add shims under the plate." (AC 43.13-1B par. 7-37)
Check gauges
- MIL-DTL-25027H Figure 3 plate nut functional alignment gage (rivet-bolt hole spacing; a test-method gage).
Sources: MS33588E · MS21047F · MIL-DTL-25027H · FAA AC 43.13-1B par. 7-37. Acceptance limits belong to the controlling spec: verify against your program's process documentation before use on hardware.
Sources
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