When turning a screwdriver, you probably expect it to tighten or loosen the screw in which it’s inserted. After all, that’s the fundamental purpose of a screwdriver: to drive screws in or out of objects. Cam-out, however, can prevent this from happening. Rather than tightening or loosening the screw, cam-out may damage it.
What Is Cam-Out?
Cam-out is a phenomenon that involves a screwdriver, or a bit, slipping out of a screw’s recess. It typically occurs when torque is applied. As you attempt to turn the screwdriver, it will slip. The screwdriver will essentially rise out of the recess while simultaneously disengaging from the screw head.
Problems Caused By Cam-Out
You can’t ignore cam-out. It can cause several problems, one of which is stripped heads. When the screwdriver rises out of the recess, it will create friction that wears down the screw head. If the damage is significant, the recess may no longer support the screwdriver. Instead, the screwdriver will sit loosely in the recess, failing to engage the head.
Cam-out increases the risk of bodily injury. Whether powered or manually operated, hand tools can cause bodily injury. If the screwdriver slips, for instance, it may strike your hand — or your hand may strike the object being screwed. Injuries such as these are typically minor, but you they are still best avoided.
Tips to Prevent Cam-Out
There are several things you can do to prevent cam-out. For starters, choose a screwdriver in the right size. It needs to match the size of the screw’s recess. Phillips head screwdrivers typically feature numerical sizes, with #000 being the smallest and #3 being the largest. Slotted or flathead screwdrivers, on the other hand, feature blade-width sizes. A 1/8″ slotted screwdriver has a blade width of 1/8 inch, whereas a 4mm slotted screwdriver has a blade width of 4 millimeters.
You should push firmly when using a screwdriver to minimize the risk of cam-out. You’ll still need to apply torque, but you need to push the screwdriver towards the screw. Otherwise, it may slip. Apply consistent and straight pressure without tilting the screwdriver.
If you’re using an electric screwdriver, you should typically start at a low RPM setting. Starting an electric screwdriver on a high RPM torque setting will only increase the risk of cam-out. Rather than engaging the head, the screwdriver may rise up and out of the recess.