When closing a snap back case back, one should do it by hand if at all possible. If the back is too tight then the Euro Tool Case Press is the best alternative available.
Twenty four dies (14 hollow A and 14 flat B) are included with your Euro Tool Case Press. Be sure that the correct size die (A) is used. Place the watch face down into Die A. Is should touch the bezel of the watch without touching the crystal. Also, be sure that the die is not touching the crown.
Put the back in place. Be sure that it is properly inserted into the bezel. Also, if a gasket is present, make sure that it is fitted properly to ensure a watertight seal. Check that the gasket is not twisted or out of place.
Use a flat die (B) which is the same size as the back of the watch. Be sure it is not too large. The flat die fits into the shaft at the top.
Press down on the press gently. You may hear a slight click. (If you don't, take the watch and examine it to see if the back is flush against the bezel all the way around.) Remember that very little pressure is required when using the Euro Tool Case Press. If you have junk watches handy it is advisable to practice the above procedure a time or two.