Screws are one of the world’s most commonly used fasteners. Consisting of a threaded shank with a pointed tip, they are used to secure two or more parts together. Driving a screw through the parts will pull them together. When installing screws, however, you should use caution not to over-torque them.
Over-torquing involves the application of excessive turning force. All screws are installed via a turning motion. Pressing and turning a screw against an object will drive it into the object. If you use too much force, you may damage the screw or object.
Breakage
Over-torquing screws can cause them to break. The head may snap off if you use too much force when turning the screw, or the shank may break at the neck below the head. Breakage such as this is common when driving screws into hard materials. You’ll need to use more force to drive screws into hard materials, which increases the risk of over-torquing and, thus, breakage.
Stripped Threads
One of the most telltale signs of over-torquing screws is stripped threads. Screws have exterior threads on the shank, which align with the interior threads of the holes in which they are driven. If you over-torque a screw, you may inadvertently strip either of these threads. When this occurs, you’ll typically have to use a new screw. The screw will fit loosely in the hole with stripped threads, rendering it useless as a fastener.
Cracks or Splintering
Another common sign of over-torquing screws is cracks or splintering. Turning a screw with too much force can cause the object in which it’s being driven to crack or splinter. Wooden objects are particularly susceptible to cracking and splintering. It typically occurs around the edges. And while cracks often start small, they can grow larger over time.
Misalignment
Over-torquing screws can result in misalignment. Like other types of fasteners, screws are used to hold multiple parts together. The parts need to be aligned with each other to ensure a secure hold. Applying too much force when installing a screw may cause the parts to shift, at which point they’ll no longer line up the way they should.
Heat Marks
You may notice heat marks if you over-torque a screw. Heat is a byproduct of friction. And the more force you use to install a screw, the more friction and heat will be produced. All of this heat can leave visible marks on the screw. You may notice a blueish tint around the head of the screw, which is indicative of excessive heat.