Yep as do most people. My main question is why add the extra step of dividing 1 by 13 when you can just do 10/13. (1/13)*10=.7692 10/13=.7692 Why include the extra step of math? Is there any situation when doing the latter would be ineffective?

It is for inspection.

Hello all! I am having a bit of trouble figuring out the proper and universal method of calculating thread depths. I have always thought that counting number of revolutions, and dividing the revolutions by threads per inch was correct, and based on the math, I think it is. Y/X=Z Variables: Y=Number of revolutions X=Threads per inch Z=Depth of threads However, in every Machinery's hanbook I've gone through, they only ever calculate by dividing 1 by threads per inch, to find pitch, then multiplying it by the number of revolutions. Y(1/X)=Z Technically: Y(1/X)=Y/X And they should be interchangeable, but I can't find anything verifying this, as everyone just uses Y(1/X)=Z. Is there any real difference between these two equations? or is there a special rule that makes it so? I would love to know!