Bevel pinion, module 1.5, 20 teeth for a 30-tooth wheel at 60° shaft angle, spherical involute — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/bevel-gear-m1-5-20t-for-30t-60deg/  (sheet CC BY 4.0; files Xem Studio Design License, https://xemstudio.com/license/)
Basis: Xem Studio design following Brown's figure (1868); true size, no printing allowance
Catalog version: 2026-10-20

Overall (mm): length 32.73, width 32.73, height 23.09
- Straight bevel gear, module 1.5 at the large end, 20 teeth, for a 30-tooth mate at 60° shaft angle: pitch cone angle 23.41°, cone distance 37.75 mm, pitch Ø30, face width 12.6 mm, Ø6 bore, Ø16.99 hub.
- Teeth are exact spherical involutes (base cone sin γb = sin δ · cos 20°), converging to the pitch apex: each flank is a cone from the apex over the spherical involute, so two such gears roll with line contact at every position; ends are spheres centred on the apex (radii A0 and A0 − F). Addendum m, dedendum 1.25 m at the large end.
- Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).

dimension  value
module (large end)  1.5
teeth  20 (mate 30)
shaft angle  60°
pitch cone  23.41°
cone distance A0  37.75 mm
face width  12.6 mm
pitch Ø  30 mm
tip Ø  32.73 mm
bore  Ø6
apex to back of hub  45.75 mm

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Henry T. Brown (1868, public domain): Five Hundred and Seven Mechanical Movements — scan on archive.org — web — Publisher's page; dimensions are facts — https://archive.org/details/fivehundredseven00browiala
- 507movements.com: Brown's movement No. 25: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_025.html
- Xem Studio: drawing — web — Publisher's page; dimensions are facts — https://xemstudio.com/objects/oblique-bevel-gears-mechanism/

Free files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/bevel-gear-m1-5-20t-for-30t-60deg/index.json
API: https://xemstudio.com/api/geometry?object=bevel-gear-m1-5-20t-for-30t-60deg