# PCB support (simplified)

A simplified PCB support post for assemblies, in four kinds (snap-in, adhesive-backed, swage, press-fit), sizes M2,
M2.5, M3 and M4, any height.

## Geometry

Stands on the XY plane at the origin along +Z; `height` is the board seat. A solid round post on a round flange:

- **snap-in**: flange from z = 0, post up to the height, a round snap head (Ø, height below) above it;
- **adhesive**: a square adhesive pad (1 mm) from z = 0, the flange on it, the post up to the height;
- **swage**, **press-fit**: flange from z = 0, post up to the height. step.parts' models of these two kinds are
  identical, so they build the same shape.

| Size | Flange Ø | Flange top | Post Ø | Snap head Ø × h | Pad (side × t) |
|---|---|---|---|---|---|
| M2 | 5.0 | 1.5 | 2.5 | 4.0 × 1.5 | 10 × 1 |
| M2.5 | 6.25 | 1.5 | 3.0 | 5.0 × 1.5 | 10 × 1 |
| M3 | 7.5 | 1.5 | 3.6 | 6.0 × 1.8 | 12 × 1 |
| M4 | 10.0 | 2.0 | 4.8 | 8.0 × 2.4 | 16 × 1 |

## Parameters

| Parameter | Meaning |
|---|---|
| `kind` | `snap-in`, `adhesive`, `swage`, `press-fit` |
| `size` | `M2`, `M2.5`, `M3`, `M4` (board hole / screw size) |
| `height` | board seat above the base, mm |
| `material` | `unspecified` (no material assigned), `nylon` (PA6), `brass`, `steel` |

## Sources

No standard covers these generic supports and they name no maker. **The geometry was measured from the published
reference models** below (every face read: the cylinders' radii and the z-ranges of their faces, the pad's planar
faces; the same dimensions for every height of a size), and every preset is checked against its own model: bounding
box within 0.05 mm and volume within 2 %.

- **step.parts**, `snap_in_pcb_support_<size>_h<height>`, `adhesive_backed_pcb_support_…`, `swage_pcb_standoff_…`,
  `press_fit_pcb_standoff_…` (https://www.step.parts, repository https://github.com/earthtojake/step.parts, commit
  c6113328, `catalog/step/`): step.parts' own "analytic simplified" models, original project material under the
  repository's **MIT** licence (© 2026 earthtojake). They name no material, so the presets have `material =
  "unspecified"`.

Simplifications (the models'): solid posts (no screw bore or thread), no snap barbs or slots, no swage collar or
press-fit knurl. Use it as an envelope in assemblies.

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