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Crossed helical (spiral) gears on shafts at 90°, 16 : 16

How do crossed helical gears connect shafts that do not meet? · Hardware · basis: Xem Studio design following Brown No. 43 (1868)

Also called: crossed helical gears, spiral gears, skew gears, screw gears, engranajes helicoidales cruzados, Schraubradgetriebe

Exact dimensions. True size, with no printing tolerance added.

sizes
5 in table

Notes

  • 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.

Crossed helical (spiral) gears on shafts at 90°, 16 : 16 size chart

parametervalue
normal module1.5
teeth16 / 16
helix45° RH both
shaft angle90°, offset
centre distance33.94 mm

Where the files are

Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.

Henry T. Brown (1868, public domain)Five Hundred and Seven Mechanical Movements — scan on archive.orgwebPublisher's page; dimensions are facts
507movements.comBrown's movement No. 43: figure, his text and an animationwebPublisher's page; dimensions are facts

Free files

★ Free files 1 parts. Xem Studio design: free to use, print and sell things from; not to be republished as files. Xem Studio Design License. index.json

crossed-helical-gears-mechanism-assemblyAssembled mechanism, all parts placed at one pose (STEP keeps each part separate)STEP · STL
Let your AI pull this. Add https://xemstudio.com/mcp to Claude, ChatGPT, Cursor or any MCP client (free, no account, one minute) and it can look up exact sizes, mating fits and free STEP/STL from every chat.
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Plain text: sheet.txt · JSON: /api/geometry?object=crossed-helical-gears-mechanism

Crossed helical (spiral) gears on shafts at 90°, 16 : 16, isometric render of a generated part
Render of crossed-helical-gears-mechanism-assembly from the free STEP; not to scale.

Fits with

Helical gear, normal module 1.5, 16 teeth, helix 45° right hand, face 12, Ø6 bore, isometric render of a generated part
Helical gear, normal module 1.5, 16 teeth, helix 45° right hand, face 12, Ø6 bore36.94×36.94×12.0 mm★ 1 file
Linear shafts Ø3 to Ø25 mm (h6), 100 to 1000 mm long, isometric render of a generated part
Linear shafts Ø3 to Ø25 mm (h6), 100 to 1000 mm long10 sizes★ 70 files

Questions

How do crossed helical gears connect shafts that do not meet?

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.