Archie,
Here is the procedure:
Remove the screw and bathe it with blue locktite. Reinsert it. Keep screwing it until when you pull the trigger the hammer does not fall anymore. Then screw it out 1/4 turn at the time until the hammer falls. At that point cock the hammer and hold it down while pulling on the trigger. Then slowly drop the hammer with your fingers. If you feel like the hammer is "catching on something" screw it out 1/4 turn more. Keep doing so until the hammer does not "catch on anything" (usually 1/4 to 1/2 turn). Let it rest overnight and you're done.