Welcome to the Onshape forum! Ask questions and join in the discussions about everything Onshape, CAD, maker project and design.

First time visiting? Here are some places to start:

  1. Looking for a certain topic? Check out the categories filter or use Search (upper right).
  2. Need support? Ask a question to our Community Support category.
  3. Please submit support tickets for bugs but you can request improvements in the Product Feedback category.
  4. Be respectful, on topic and if you see a problem, Flag it.

If you would like to contact our Community Manager personally, feel free to send a private message or an email.

Gear Sizing based on power transmitted

srinath_mallikarjunan808srinath_mallikarjunan808 Member Posts: 3 PRO

Suppose i want a reduction ratio of 10 to 1 using spur gears, i could chose the diameters to be 1000mm to 100mm or 100mm to 10mm. 'Theoretically' based on the no slip condition at the interface, the ratio is all that matters.

But in practise, it seems apparent that there must be a minimum gear size necessary to transmit a particular amount of power/torque. (This could change depending on material of constrution)

I am not sure how to do this calculation. Could someone provide me a link/calculator.

What if i wanted to do this for planetary gears ?
Are there any specific advantages, disadvantages that i need to be aware of.

My goal is twin counter-rotating coaxial shafts with sufficient reduction and driven by a single IC engine.


  • konstantin_shiriazdanovkonstantin_shiriazdanov Member Posts: 537 ✭✭✭✭
    i would actually ask google "spur gear calculator", but for high reliability applications one should be careful and use methods which are approved by national or industrial standarts, recomended matirials and so on. specifically about 10/1 ratio in one stage and counter rotationg coaxial shafts could be achived by cyclo gears
Sign In or Register to comment.