# Miter gear

Straight miter gear, 1:1, as an envelope for assemblies. Axis along Z, back on the XY plane.

## Geometry

The published outline: the hub, the back cone out to the outside diameter D at the crown (G above the back), a 45° cone up to the total length F, and the bore. `detail = "full"`
cuts the teeth into it, each gap running along the pitch cone to the apex. Tooth sections use Tredgold's approximation: the involute of the equivalent spur gear of z / cos 45° teeth,
with ISO 53 proportions (20°, addendum 1.0 m, dedendum 1.25 m). This is close for looks and fits; it isn't a tooth-contact model. `detail = "simple"` keeps the teeth filled in.

## Source

KHK Gears, catalogue 2025, Miter Gears, SM table (carbon steel, straight), PDF p. 26, <https://khkgears.us/media/lblpmezm/catalog-2025-miter-gears.pdf>.
The 45° tip cone is this outline's simplification, checked against the table: (D − B)/2 and (G − H) agree on these sizes.

| Number | Module | Teeth | Bore A | Hub B | Outside D | Total F | Crown to back G | Hub width H |
|---|---|---|---|---|---|---|---|---|
| SM1-20 | 1 | 20 | 6 | 16 | 21.41 | 13.94 | 10.71 | 8 |
| SM1-25 | 1 | 25 | 6 | 20 | 26.41 | 15.16 | 11.21 | 8 |
| SM1-30 | 1 | 30 | 8 | 24 | 31.41 | 17.71 | 13.71 | 10 |
| SM1.25-20 | 1.25 | 20 | 8 | 22 | 26.77 | 15.27 | 11.38 | 9 |
| SM1.25-25 | 1.25 | 25 | 8 | 25 | 33.02 | 17.88 | 13.26 | 9.25 |
| SM1.25-30 | 1.25 | 30 | 10 | 30 | 39.27 | 23.47 | 18.13 | 13.5 |
| SM1.5-20 | 1.5 | 20 | 8 | 26 | 32.12 | 21.24 | 16.06 | 13 |
| SM1.5-25 | 1.5 | 25 | 10 | 30 | 39.62 | 22.25 | 16.31 | 11.5 |
| SM1.5-30 | 1.5 | 30 | 10 | 36 | 47.12 | 28.24 | 21.56 | 16 |
| SM2-16 | 2 | 16 | 10 | 27 | 34.83 | 19 | 15.41 | 11.5 |
| SM2-20 | 2 | 20 | 12 | 34 | 42.83 | 24.89 | 18.41 | 14 |
| SM2-25 | 2 | 25 | 12 | 40 | 52.83 | 24.33 | 16.41 | 10 |
| SM2-30 | 2 | 30 | 12 | 45 | 62.83 | 29.42 | 21.41 | 12.5 |
| SM2.5-16 | 2.5 | 16 | 12 | 34 | 43.53 | 21 | 16.77 | 12 |
| SM2.5-20 | 2.5 | 20 | 14 | 42 | 53.54 | 32.54 | 24.77 | 19 |
| SM2.5-25 | 2.5 | 25 | 16 | 50 | 66.04 | 30.41 | 20.52 | 12.5 |
| SM2.5-30 | 2.5 | 30 | 16 | 60 | 78.54 | 36.28 | 26.27 | 17 |
| SM3-16 | 3 | 16 | 14 | 42 | 52.24 | 23 | 18.12 | 13 |
| SM3-20 | 3 | 20 | 16 | 50 | 64.24 | 39.84 | 30.12 | 23 |
| SM3-25 | 3 | 25 | 20 | 60 | 79.24 | 37.81 | 24.62 | 15 |
| SM3-30 | 3 | 30 | 20 | 70 | 94.24 | 45.47 | 32.12 | 20 |

Maker names identify the source; this part isn't made by or affiliated with KHK. Module 0.8 and teeth 24, 36 aren't in this table and aren't offered.