Thanks, this is what I needed, now I understand what I was missing. I missed the part of figuring the pitch circle circumference. I'm going to have to go back and review that section of the book again. If this gear was a triple threaded worm gear with the same criteria as that problem, would I still figure out the pitch diameter the same way? Any help you can give me on the others will be greatly appreciated. When I get to the exam for this class I have to be able to write down how I arrived at the answers for these types of questions, whether I used a calculator or not. So thanks again for you help.