# NEMA stepper motor

Hybrid stepper motor envelope for assemblies, NEMA frame sizes 8, 11, 14, 17, 23 and 34.

## Geometry

The mounting face is on the XY plane at the origin. The square body runs along -Z for `body_length`; the pilot and the
shaft stand along +Z. Four mounting holes on a square pattern (threaded holes are drawn at their nominal diameter). The
shaft's D-flat faces +Y where the frame has one. Windings, end bell, wires and connector aren't modelled, and neither is
the key on a NEMA 34 shaft (5 mm wide, 25 mm long on the data sheet).

## Parameters

| Parameter | Meaning |
|---|---|
| `frame` | `NEMA8`, `NEMA11`, `NEMA14`, `NEMA17`, `NEMA23`, `NEMA34` |
| `body_length` | Mounting face to the back of the motor, mm. Not fixed by the frame size: it is the maker's choice |
| `shaft_diameter` | 4, 5, 6.35, 8, 12.7 or 14 mm, as the frame allows |

## Source

- **All frames:** Leadshine Technology, *CM Series Stepper Motors* data sheet, (c) 2018, section 2.3 Motor Specifications,
  printed pp. 07 to 14, drawings and model tables, as hosted by a distributor:
  <https://cdn.shopify.com/s/files/1/0250/8347/8109/files/Leadshine_Hybrid_Stepper_Motor_CM_Series_Data_Sheet.pdf>
- **NEMA 17 side (42.3 max), hole depth (4.5 min), pilot height (2):** Changzhou Songyang (SOYO) *SY42STH47-1206A*
  technical conditions sheet, <https://www.pololu.com/file/0J685/SY42STH47-1206A.pdf>. Leadshine draws 42 square, depth 4,
  pilot 1.8.
- **NEMA 34 pilot height:** Novanta, *NEMA 34 motors* data sheet, 2022 (2.5 +-0.5 mm),
  <https://novanta.com/robotics-automation/wp-content/uploads/sites/3/2026/01/Nema34_motors_2022.pdf>.
- **17HS4401 body length (40 mm):** Handson Technology, *17HS4401S* data specs, p. 2,
  <https://www.handsontec.com/dataspecs/17HS4401S.pdf>. That sheet draws a 42.0 max square and a 23 mm shaft; the preset
  uses this recipe's NEMA 17 frame table (42.3 and 24).

| Frame | Side | Hole spacing | Holes | Pilot Ø × height | Shaft Ø | Shaft length | Flat |
|---|---|---|---|---|---|---|---|
| NEMA 8 | 20.3 | 15.4 | M2 × 2 | 16 × 1.5 | 4 | 10 | none drawn |
| NEMA 11 | 28.2 | 23 | M2.5 × 2.5 | 22 × 2 | 5 | 20 | 4.5 across, 15 long |
| NEMA 14 | 35.2 | 26 | M3 × 4.5 | 22 × 2 | 5 | 24 | 4.5 across, 15 long |
| NEMA 17 | 42.3 | 31 | M3 × 4.5 | 22 × 2 | 5 | 24 | 4.5 across, 15 long |
| NEMA 23 | 56.4 | 47.14 | Ø5 through a 5 flange | 38.1 × 1.6 | 6.35 or 8 | 21 | 5.8 or 7.5 across, 15 long |
| NEMA 34 | 86 | 69.6 | Ø5.5 through a 10 flange | 73 × 2.5 | 12.7 or 14 | 32 | key, not drawn |

Every row is in `part.py` (`FRAMES`, `SHAFTS`, `BODY_RANGE`).

Body lengths are limited per frame to the range of the sourced models (`BODY_RANGE`): a length outside it has no maker's
data, so the recipe refuses it. Motor names in the presets identify the sizes those makers publish; this part is not made
by or affiliated with any of them. Drawing tolerances vary by maker and are not stated here.

Preset list: frame sizes of the step.parts catalogue (MIT) and the makers' models above, see `library/NOTICE.md`.