# Inch specialty nuts (ASME B18.16.6 / B18.2.2 / SAE J483)

Nylon-insert and all-metal lock nuts, hex flange nuts and acorn (cap) nuts for Unified inch threads #2-56 to 1/2-20.
Presets cover the catalogue's inch nylon-insert, all-metal, flange and acorn nuts.

## Geometry

Envelope for assemblies at the tables' maximum sizes. Axis along +Z, sitting on the XY plane, centred on the origin;
a hexagon's corners point along X. The thread is a plain bore at the ASME B1.1 basic major diameter D (not
modelled); corner chamfers are not modelled. The model is in millimetres (1 in = 25.4 mm).

- **nylon**, **all-metal**: a hex prism, width across flats **s** (max), overall height **h** (max). The nylon
  insert's collar and the all-metal nut's locking deformation lie within that envelope and are not modelled.
- **flange**: a flange disc **dc** (max) × **c** (min, the flange's edge thickness) under a hex prism **s** (max)
  up to the overall thickness **m** (max). The flange's taper from its edge up to the hex is not modelled.
- **acorn**: a hex prism **F** (max) × **Q** (hex height); above it the crown, a body of diameter **A** up to the
  overall height **H** whose top is rounded with the body radius **S** (a sphere of radius S whose top is at H;
  the nose radius R is not modelled); a blind bore **T** (max drill depth) deep.

## Parameters

| Parameter | Meaning |
|---|---|
| `size` | Thread, #2-56 to 1/2-20 (UNC and UNF) |
| `style` | `nylon` (#2 and up), `all-metal` (#4 and up), `flange` (#6 and up), `acorn` (#6 and up) |
| `material` | `steel` (zinc plated), `stainless-18-8` (304) |

## Sources

Values in inches, as printed. Copies consulted: globalfastener.com's reproductions of the ASME tables (dimension
facts), cross-checked as noted.

- **Nylon-insert lock nuts**: ASME B18.16.6-2017, style **NM** (machine-screw sizes, standard height;
  https://www.globalfastener.com/standards/detail_4855.html) and style **NE** (standard height;
  https://www.globalfastener.com/standards/detail_4859.html). Cross-checks: Conquest Fasteners "NE Nylon Insert
  Locknuts" specification p. 1 (https://www.fastenersplus.com/cdn/shop/files/CQ-NE-Locknuts-Spec.pdf) agrees on NE h
  and m; Albany County Fasteners "US Nylon Inserted Hex Lock Nut Size Chart" (2023) agrees on NM s max and h max.
  Disagreement (not used by the model): NE s min 5/16 .489, 3/8 .551, 1/2 .736 on the NE page against .492, .553,
  .741 in Conquest's sheet.
- **All-metal lock nuts**: ASME B18.16.6-2017, "Prevailing Torque All-Metal Type Hex Nuts"
  (https://www.globalfastener.com/standards/detail_4852.html).
- **Hex flange nuts**: ASME B18.2.2-2015 **Table 12** "Hex Flange Nuts"
  (https://www.globalfastener.com/standards/detail_4555.html).
- **Acorn nuts**: SAE J483a, low crown, as reproduced by AmesWeb "Acorn Nut Dimensions (Inch Series)", which cites
  SAE J483a via Machinery's Handbook, 30th edition
  (https://amesweb.info/Fasteners/NutsInchSeries/AcornHighLowCrownNutDimensions.aspx). Cross-check: Kent Automotive
  grade 2 acorn nuts (https://www.kent-automotive.com/collections/acorn-nuts-wf4510/products.json) agree on the
  overall height H and the thread depth for #6 to 1/2.

| Size | D | Nylon s × h | All-metal s × h | Flange s / dc / m / c | Acorn F / Q / A / H / S / T |
|---|---|---|---|---|---|
| #2 | .086 | .251 × .153 (NM) | – | – | – |
| #4 | .112 | .251 × .153 (NM) | .251 × .163 | – | – |
| #6 | .138 | .313 × .188 (NM) | .313 × .171 | .312 / .422 / .171 / .02 | .3125 / .16 / .30 / .34 / .17 / .25 |
| #8 | .164 | .345 × .239 (NM) | .345 × .191 | .344 / .469 / .203 / .02 | .3125 / .16 / .30 / .34 / .17 / .25 |
| #10 | .190 | .376 × .249 (NM) | .376 × .241 | .375 / .500 / .219 / .03 | .375 / .19 / .36 / .41 / .22 / .28 |
| 1/4 | .250 | .439 × .328 (NE) | .4385 × .288 | .438 / .594 / .236 / .04 | .4375 / .22 / .41 / .47 / .25 / .34 |
| 5/16 | .3125 | .502 × .359 (NE) | .5020 × .336 | .500 / .680 / .283 / .04 | .500 / .25 / .47 / .53 / .28 / .41 |
| 3/8 | .375 | .564 × .468 (NE) | .5645 × .415 | .562 / .750 / .347 / .04 | .5625 / .28 / .53 / .62 / .33 / .45 |
| 1/2 | .500 | .752 × .609 (NE) | .7520 × .573 | .750 / 1.031 / .458 / .05 | .750 / .38 / .72 / .81 / .42 / .59 |

D: ASME B1.1 basic major diameter. Not covered (no source has them): #0 in every style; #2 all-metal, flange and
acorn; #4 flange and acorn (an 18-8 #4-40 acorn nut is sold, but no source gives its crown).

Preset list: sizes of the step.parts catalogue (MIT), see `library/NOTICE.md`.