# Stud bolt set

Complete stud-bolt set for one flanged joint: stud count, diameter and RF length from the ASME B16.5 bolting tables, threaded A193 B7 studs with chamfered ends and B7 end marks, two A194 2H heavy hex nuts each with washer face and 2H mark, set at a made-up joint grip so a few threads protrude. Coating: PTFE blue, hot-dip galvanised, black or zinc-nickel. Laid out on the bolt circle or in a row.

**Standards:** ASME B16.5, ASME B18.2.2, ASTM A193 B7, ASTM A194 2H, ASME PCC-1

## Installation

```bash
npx -y https://decktwin.com/cli/deck-twin-0.2.2.tgz add stud-bolt-set
```

Copies `piping/stud-bolt-set.tsx`, any helper files it imports and the shared `lib/` into `src/components/deck-twin/`. Needs `three`, `@react-three/fiber` and `@react-three/drei`.

## Usage

```tsx
import { Canvas } from '@react-three/fiber'
import { OrbitControls } from '@react-three/drei'
import { Stage } from './components/deck-twin/lib/stage'
import { StudBoltSet } from './components/deck-twin/piping/stud-bolt-set'

export default function Scene() {
  return (
    <Canvas shadows camera={{ position: [8, 5, 9], fov: 35 }}>
      <Stage>
        <StudBoltSet />
      </Stage>
      <OrbitControls makeDefault />
    </Canvas>
  )
}
```

## Props

| Prop | Type | Default | Range |
| --- | --- | --- | --- |
| `nps` | `number (NPS, in)` | `6` |  |
| `rating` | `150 \| 300 \| 600 \| 900 \| 1500 \| 2500` | `300` |  |
| `coating` | `"ptfe-blue" \| "hot-dip" \| "black" \| "zinc-nickel"` | `"ptfe-blue"` |  |
| `layout` | `"joint" \| "row"` | `"joint"` |  |
| `...group` | position, rotation, scale… |  |  |

## P&ID

Not drawn on P&IDs; in joint details, studs are lines through both flanges with a hex nut at each end, specified in the bill of materials by number, diameter and length.

tag STUD · Piping class item (ASME B16.5 bolting, ASTM A193 / A194); not drawn on P&IDs

Quantity and size come from ASME B16.5 tables for the NPS and class; coating from the piping or coating specification.

Piping class / bolting specification (ASME B16.5, ASTM A193 B7 / A194 2H) fields and the props they set:

| Field | Prop |
| --- | --- |
| Nominal size | `nps` |
| Pressure class | `rating` |
| Coating | `coating` |

## Typical suppliers

Fabory. The geometry is generic and sized from public standards. It is not vendor CAD.

## Source

`piping/stud-bolt-set.tsx`. This is the component file only: it imports shared code, so install it with the command above rather than pasting it alone. https://decktwin.com/r/stud-bolt-set.json has every file.

```tsx
// Flange stud-bolt set per ASME B16.5 bolting tables: ASTM A193 B7 threaded studs with chamfered ends, two A194 2H heavy hex nuts each, optional coating.
import * as THREE from 'three'
import type { Kit, MatKey } from '../lib/kit'
import { paint } from '../lib/materials'
import { KitMesh, useKit, type GroupProps } from '../lib/mesh'
import { GASKET_SPIRAL_WOUND, flange as flangeDims, studLength, type Rating } from '../lib/standards'
import { textMaterial } from '../lib/textures'

export type Coating = 'ptfe-blue' | 'hot-dip' | 'black' | 'zinc-nickel'

export interface StudBoltSetProps {
  nps?: number
  rating?: Rating
  coating?: Coating
  /** as installed on the bolt circle (joint), or laid out in a row */
  layout?: 'joint' | 'row'
}

export const defaults = { nps: 6, rating: 300 as Rating, coating: 'ptfe-blue' as Coating, layout: 'joint' as 'joint' | 'row' }

const COAT: Record<Coating, string> = { 'ptfe-blue': '#27427a', 'hot-dip': '#a9adb0', black: '#1f2124', 'zinc-nickel': '#c9cbb8' }

export function StudBoltSet({ nps = defaults.nps, rating = defaults.rating, coating = defaults.coating, layout = defaults.layout, ...group }: StudBoltSetProps & GroupProps) {
  const data = useKit((k) => build(k, nps, rating, coating, layout), [nps, rating, coating, layout])
  return (
    <group {...group}>
      <KitMesh data={data} />
    </group>
  )
}

export default StudBoltSet

// UNC threads per inch by nominal diameter (8-UN from 1")
const TPI: [number, number][] = [[0.5, 13], [0.625, 11], [0.75, 10], [0.875, 9]]
const pitch = (d: number) => 0.0254 / (TPI.find(([dia]) => d <= (dia + 0.06) * 0.0254)?.[1] ?? 8)

/** One stud along +X centred at the origin: threaded body as a lathe with a real thread profile, 45° chamfered ends. */
function stud(k: Kit, mat: MatKey, d: number, L: number) {
  const p = pitch(d)
  const r = d / 2
  const rr = r - p * 0.54
  const ch = p * 1.2
  const prof: [number, number][] = [[0, -L / 2], [rr, -L / 2], [r, -L / 2 + ch]]
  for (let y = -L / 2 + ch; y < L / 2 - ch - p; y += p) prof.push([r, y + p * 0.12], [rr, y + p * 0.5], [r, y + p * 0.88])
  prof.push([r, L / 2 - ch], [rr, L / 2], [0, L / 2])
  k.lathe(mat, prof, [0, 0, 0], 'x', 10)
}

/** A194 2H heavy hex nut: across flats 1.5d + 1/8", height d, washer face against the flange, chamfered outer face with the grade mark. */
function nut(k: Kit, mat: MatKey, d: number, x: number, out: 1 | -1) {
  const af = 1.5 * d + 0.0032
  const ac = af / Math.cos(Math.PI / 6)
  k.hex(mat, ac * 0.985, d * 0.92, [x, 0, 0], 'x')
  k.cyl(mat, af * 0.48, d * 0.05, [x - out * d * 0.485, 0, 0], 'x', 24)
  k.cyl(mat, out > 0 ? af * 0.5 : af * 0.44, d * 0.03, [x + out * d * 0.475, 0, 0], 'x', 24, out > 0 ? af * 0.44 : af * 0.5)
  k.plane(textMaterial('2H', COAT_TXT, '#f2f2f2', 64, 64), af * 0.24, af * 0.24, [x + out * (d * 0.492), af * 0.3, 0], new THREE.Quaternion().setFromAxisAngle(new THREE.Vector3(0, 1, 0), (out * Math.PI) / 2))
}
const COAT_TXT = '#222831'

function build(k: Kit, nps: number, rating: Rating, coating: Coating, layout: 'joint' | 'row') {
  const f = flangeDims(nps, rating)
  const d = f.boltDia
  const L = studLength(nps, rating)
  const mat: MatKey = coating === 'ptfe-blue' ? 'boltXylan' : paint(COAT[coating], { metalness: 0.6, roughness: 0.4, clearcoat: 0, weather: 0 })
  // nut positions for a made-up RF joint: grip = two flanges + faces + gasket, nut height = d
  const grip = 2 * (f.thickness + f.raisedFaceHeight) + GASKET_SPIRAL_WOUND
  const xn = grip / 2 + d * 0.46
  const place = (fn: () => void, pos: THREE.Vector3) => k.with(new THREE.Matrix4().makeTranslation(pos.x, pos.y, pos.z), fn)
  const each = (pos: THREE.Vector3) =>
    place(() => {
      stud(k, mat, d, L)
      nut(k, mat, d, -xn, -1)
      nut(k, mat, d, xn, 1)
      k.disc(textMaterial('B7', '#3a3f45', '#f2f2f2', 64, 64), d * 0.32, [L / 2 + 0.0003, 0, 0], 'x', 16)
    }, pos)
  for (let i = 0; i < f.bolts; i++) {
    if (layout === 'row') each(new THREE.Vector3(0, d / 2 + d * 0.9, (i - (f.bolts - 1) / 2) * d * 3.2))
    else {
      const a = Math.PI / f.bolts + (i / f.bolts) * Math.PI * 2
      each(new THREE.Vector3(0, -Math.sin(a) * (f.boltCircle / 2), Math.cos(a) * (f.boltCircle / 2)))
    }
  }
}
```