Small wind / Buyer questions
Mechanical interfaces
Does equal gear module prove that a pinion matches a ring gear?
The short answer
No. Module describes a tooth-size relationship, but pressure angle, tooth system and other geometry must also match. A pinion that appears to have the right tooth spacing can still be incompatible with a wind-yaw ring gear. Use the complete mating definitions rather than module alone.
Identify the module convention
Spur and helical gears can use different reference planes, and normal module is not automatically the same as transverse module. Units and the applicable tooth standard also matter. Gear count and outside diameter can help describe a part, but they do not uniquely recover its complete tooth geometry. Profile shift, addendum modifications and tip relief can further distinguish gears with similar visible dimensions.
Check the actual tooth pair
Matching pressure-angle systems and compatible profiles are necessary parts of a mesh assessment. Centre distance, internal versus external gearing and permitted contact geometry also enter. A correct nominal ratio does not establish proper flank contact or adequate root clearance. KHK technical material illustrates gear dimensions as a combination of parameters; Rothe Erde treats its ring gearing and matching pinion as a specific interface.
Request a mating gear data set
Ask for module and reference plane, pressure angle, tooth counts, helix details if present, profile modifications, face geometry and operating centre distance. Have the supplier confirm the specific pinion/ring pair and its rating. MARSTON gear construction and tooth parameters are unconfirmed. Do not infer interchangeability from a module stamp, scale a photograph or machine a replacement from partial dimensions. The selection decision requires compatible tooth geometry before load capacity can be evaluated. For helical gearing, record helix hand and the normal/transverse parameter convention together. A module match in one plane cannot resolve a mismatch in another, even where the two outside diameters appear compatible.
Sources
Examples are illustrative. Confirm product-specific performance, compatibility and supply scope in the applicable documents.