28) Find the change gear (driven gear) to cut 2.5mm pitch thread using a lathe having lead screw of pitch 5mm with driver gear 60 teeth?

29) Calculate the driven gear to cut 1.5mm pitch thread on a job using a lathe having lead screw of 5mm pitch with driver gear of 30 teeth?

30) Calculate the driven gear to cut 2mm pitch on a job using a lathe having lead screw of 4mm pitch with driven gear 50 teeth?

31) Calculate the driven gear to cut 1.5mm pitch thread on a job using a lathe having lead screw of 4mm pitch with driver gear 30 teeth?

32) Which method of threading is used in mass production?