while designing an spur gear I have learned most of term specification , Terminology and formula for equation 

for designing an gear its most important to understand about gear terminology and specification 

if you know about module , no of teeth and pressure angle ,then you can easily find out an other specification and values of gear and tooth profile specification 

1. for selection of material for gear is also very important term for large size gear = gray cast iron (cheaper and generate less noise , good wear resistance)
2. for medium Duty = Plain Carbon Steel
3. for heavy duty = Alloy Steel
4. ​​​​​​​ ​​​​​​​

Edu ​​​​​​​