What is the formula of gear ratio for cutting threads?
1
\(\frac { DRIVER } { DRIVEN }=\frac {Lead ~of~ Work}{ Lead of~Lead~Screw}\)
2
\(\frac{ DRIVER }{ DRIVEN }=\frac{ PITCH~OF~ WORK }{ LEAD~OF~LEAD~SCREW }\)
3
\(\frac{DRIVER } { DRIVEN }=\frac { LEAD~OF~ LEAD~SCREW } {LEAD~ OF~ WORK }\)
4
\(\frac { DRIVER }{ DRIVEN }=\frac{PITCH ~OF ~LEAD~SCREW }{ LEAD~OF ~LEAD~SCREW }\)