Drawing
Selection table
One row per thread size, with its own link (/parts/nutplates/ms21075/#MS21075-04). The part number shown is the plain-hole form; the letters below change finish and holes, not size.
| Part no. | Thread | A max | B max | C | J | H max | Ø K | Axial, lbf min |
|---|---|---|---|---|---|---|---|---|
| MS21075-04 | 4-40 | .651 | .315 | .203 | .406 | .153 | .098 | 750 |
| MS21075-06 | 6-32 | .682 | .357 | .218 | .437 | .171 | .098 | 1,130 |
| MS21075-08 | 8-32 | .707 | .367 | .234 | .468 | .250 | .098 | 1,720 |
| MS21075-3 | 10-32 | .739 | .416 | .250 | .500 | .250 | .098 | 2,460 |
| MS21075-4 | 1/4-28 | .801 | .500 | .281 | .562 | .281 | .098 | 4,580 |
| MS21075-5 | 5/16-24 | 1.010 | .581 | .359 | .718 | .328 | .130 | 7,390 |
Inches. From Table I of MS21075 Rev. H (28 Mar 1995). C ±.005, J ±.002, K +.005 −.000 as toleranced on the sheet. Ø P is the maximum barrel diameter. Weight is the standard's figure per 100 pieces. Rows shown are the sizes this sheet covers; the standard may list more.
How to read the part number
| Part no. | Meaning |
|---|---|
| MS21075-08 | Plain rivet holes |
The standard lists no K (countersunk or dimpled hole) version for these sizes. This standard's dash numbers carry no L form.
What it is for
Miniature floating self-locking nutplate with reduced rivet spacing. Rated to 450 °F.
The nut floats in its retainer, which absorbs some hole misalignment between the nutplate and the part bolted to it.
Choose the size from the screw thread, then confirm J and C against the hole pattern and the edge distance of the flange it rivets to.
Limits — when NOT to use this
- Approved data governs. Use the nutplate and rivets the maintenance manual or IPC specifies.
- The MS sheet is a public-domain revision. These MS standards were later replaced by NASM equivalents. Check the current revision before buying to a drawing.
- Grip with nutplates. Where the proper bolt grip is not available, AC 43.13-1B par. 7-37 says to add shims under the plate, not washers.
- Rivets for the lugs, and their edge distance, come from the repair data, not from this sheet.
Sources
- MS21075 Rev. H, 28 Mar 1995 — Nutplate, Self-Locking, Two Lug, Low Height, Floating, Miniature — Table I, dash numbers and dimensions; notes and requirements. Public domain, distribution unlimited.
- FAA AC 43.13-1B, par. 7-37 — shims, not washers, under plate nuts.