The invention belongs to the field of 
assembly of small-
caliber bullets, and in particular relates to a screw-in type electric primer explosion-proof screwing 
machine used in the 
assembly of small-
caliber bullets.  A screw-in type electric primer explosion-proof tightening 
machine of the present invention includes a 
cartridge cup, a jacking mechanism, a positioning and clamping mechanism, a pit device for automatically pressurizing and searching for a screw-in type electric primer, an air circuit 
system, a control part and  controlling 
software.  The jacking mechanism of the screw-in electric primer explosion-proof screwing 
machine is installed on the machine base, the 
cartridge cup is located above the jacking mechanism, and the positioning and clamping mechanism, automatic pressurization and the pit device for finding the screw-in electric primer are located in the 
cartridge in turn.  The top of the cylinder cups are installed on the rack.  The air source, valve, air 
pipe and the pneumatic actuators of the above mechanical parts form an air circuit 
system.  The 
control software is set in the controller of the control part, and the controller and the 
control software control the operation of the above-mentioned mechanical structure.  The screw-in electric primer explosion-proof tightening machine of the present invention can automatically complete the screwing of the screw-in electric primer, it solves the problem of automatically finding the pit on the screw-in electric primer, and can ensure the precision control of the screw-in electric primer tightening depth  , to 
ensure product quality, realize the separation of man and machine, and ensure the safety of production personnel.