Why factory always request PDF and STP two drawings when start to produce ?
This is very easy to answer : becasue for CNC machining , we always need STP files to make program . then debug machine .
For the PDF files , when we inspection , we need according the PDF tolerance to inspect it ,ensure all size is correct .
If you only design STP files , no PDF , you can tell us the tolerance , then we will according your request to do it .
More tolerance standrad , you can see our CNC machining page :
About the drawings , just make a refer for you :