Crossed helical (spiral) gears on shafts at 90°, 16 : 16 — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/crossed-helical-gears-mechanism/  (sheet CC BY 4.0; files Xem Studio Design License, https://xemstudio.com/license/)
Basis: Xem Studio design following Brown No. 43 (1868)
Catalog version: 2026-10-20

Sizes: see table below
- Two helical gears of the same hand on shafts that cross without meeting: the shaft angle equals the sum of the helix angles (45° + 45° = 90° here). The teeth touch at a point and slide along each other, so they suit light loads — instrument drives, distributor and oil-pump drives.
- Normal module 1.5, 16 teeth, 45° right hand on both: pitch Ø33.94 each (m_n·N / cos β), shafts 33.94 mm apart; ratio 1 : 1 (N₂/N₁, not the diameters). The second gear's phase was found by search to the touching position.
- Brown's No. 43 (gears transmitting rotary motion between shafts arranged obliquely, another form).
- Parts (each has its own page): crossed-helical-gear-mn1-5-16t-beta45-rh-bore6, linear-shafts-h6.
- Brown's movement No. 43 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.

parameter  value
normal module  1.5
teeth  16 / 16
helix  45° RH both
shaft angle  90°, offset
centre distance  33.94 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. 43: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_043.html

Free files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/crossed-helical-gears-mechanism/index.json
API: https://xemstudio.com/api/geometry?object=crossed-helical-gears-mechanism