Spur gears, module 1.25: 10 to 80 teeth (20° involute) — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/spur-gears-module-1-25/  (CC BY 4.0)
Basis: ISO 53 basic rack: 20° pressure angle, addendum m, dedendum 1.25 m; pitch Ø = m × teeth, tip Ø = m × (teeth + 2), root Ø = m × (teeth − 2.5)
Catalog version: 2026-10-20

Sizes: see table below
- Centre distance of two module 1.25 gears = m × (N1 + N2) / 2. Face width 10 mm, plain bore (add a hub, key or set screw to suit). Teeth below 17 are drawn without profile shift, so they undercut as real unshifted gears do.

teeth  pitch_dia_mm  tip_dia_mm  root_dia_mm  face_mm  bore_mm
10  12.5  15.0  9.38  10.0  3
12  15.0  17.5  11.88  10.0  4
14  17.5  20.0  14.38  10.0  5
15  18.75  21.25  15.62  10.0  5
16  20.0  22.5  16.88  10.0  6
18  22.5  25.0  19.38  10.0  7
20  25.0  27.5  21.88  10.0  8
22  27.5  30.0  24.38  10.0  9
24  30.0  32.5  26.88  10.0  9
25  31.25  33.75  28.12  10.0  10
28  35.0  37.5  31.88  10.0  11
30  37.5  40.0  34.38  10.0  12
32  40.0  42.5  36.88  10.0  13
35  43.75  46.25  40.62  10.0  14
36  45.0  47.5  41.88  10.0  15
40  50.0  52.5  46.88  10.0  16
42  52.5  55.0  49.38  10.0  17
45  56.25  58.75  53.12  10.0  19
48  60.0  62.5  56.88  10.0  20
50  62.5  65.0  59.38  10.0  21
56  70.0  72.5  66.88  10.0  23
60  75.0  77.5  71.88  10.0  25
64  80.0  82.5  76.88  10.0  25
70  87.5  90.0  84.38  10.0  25
72  90.0  92.5  86.88  10.0  25
80  100.0  102.5  96.88  10.0  25

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- ISO: ISO 53 standard basic rack (20° pressure angle, addendum 1 m, dedendum 1.25 m) and ISO 54 modules — standard — ISO; dimensions are facts [verify license at link] — https://www.iso.org/standard/5768.html

Free files (CC BY 4.0, Xem Studio; STEP + STL, 26 parts): https://xemstudio.com/files/hardware/spur-gears-module-1-25/index.json
API: https://xemstudio.com/api/geometry?object=spur-gears-module-1-25