Don’t Use Screws That Are TOO LONG or TOO SHORT! (Screw Length/How To Choose The Right Screw Length)
Screws that measure 2 1/2 inches are more appropriate for two-by-fours placed flat, allowing you to bury the head as needed. If you’re angling the screw, such as in a toenail application, or when end nailing—driving through the broad face of one two-by-four and into the edge or end of another—you can use longer screws.