GearXYZ

Engineering Resources

Set of tools and resources for GearXYZ.

Backlash

Common Modules

Gear Tooth Measurement

Profile Shift

Specific Sliding

Backlash

Minimum backlash values for gears are based on the standards for AGMA, DIN and ISO.

AGMA Backlash

DIN Backlash

DIN backlash values are based on the module size, centerd distance, application and manufacturing tolerances.

ApplicationTypical Backlash
Precision gears0.05m to 0.08m
General purpose0.08m to 0.1m
Heavy-duty applications0.1m to 0.15m

ISO Backlash

  • Module size
  • Centerd distance

Common Modules

DIN 780 list of modules for both fine and coarse pitch gears. Series I are the preferred modules, Series II are the extended modules. Use preferred modules for better availability and lower cost.

Fine Pitch (m < 1)

Series ISeries II
0.05-
-0.055
0.06-
-0.07
0.08-
-0.09
0.1-
-0.11
0.12-
-0.14
0.16-
-0.18
0.2-
-0.22
0.25-
-0.28
0.3-
-0.35
0.4-
-0.45
0.5-
-0.55
0.6-
-0.65
0.7-
-0.75
0.8-
-0.85
0.9-
-0.95

Coarse Pitch (m ≥ 1)

Series ISeries II
1-
-1.125
1.25-
-1.375
1.5-
-1.75
2-
-2.25
2.5-
-2.75
3-
-3.25
-3.5
-3.75
4-
-4.25
-4.5
-4.75
5-
-5.25
-5.5
-5.75
6-
-6.5
-7
8-
-9
10-
-11
12-
-14
16-
-18
20-
-22
25-
-28
32-
-36
-39
40-
-42
-45
50-
-55
60-
-70

Tooth Thicknesss Measurements

Tooth thicknesss measurements for gears are based on the standards for AGMA, DIN and ISO.

Span

Measurement Over Pins / Measurement Under Pins

DIN backlash values are based on the module size, centerd distance, application and manufacturing tolerances.

Gear Tooth Vernier Caliper

Profile Shift

Profile shift is used to adjust the gear size to acheive a specific center distance. The split of it in a gearset is optimised for strength or specific sliding. It is also used to adjust the gear size to acheive a specific backlash. This means there are multiple profile shifts for a given gear but the simplified way to think about them is. There is the nominal profile shift that is used to find the center distance at zero backlash. Backlash is then applied to find the Profile Shift for manufacturing. This profile shift for manufacturing is used for the hobbing and inspection process. There is often a third to describe the O.D of the gearing but is is better applied as a correction factor k as stated ISO 21771. O.D. of gearing is turned often in a seperate maching process from hobbing and makes more sense as to be adjusted from the nominal.

Specific Sliding