Original post by: Minho ,
This is a fairly common question here on the iFixit Answers Forum. Unfortunately, there is no good answer. Most of the screw kits available, both here at iFixit and elsewhere online, are basically just jumbled together in a bag. The only way to find the proper replacement screw is to measure them with a digital caliper to insure you have the right one. That combined with following the appropriate iFixit guide that shows the screw lengths. Apple uses a huge array of screws with different lengths, thread type and width. In certain areas, like the screen connector bracket, putting the wrong screw in the wrong hole can kill your device (this is referred to as Long-Screw Damage).