The wrench driving style is still an uncommon driving style for most people to simply encounter.
This unusual tip makes the screws more resistant to tampering and removal without the proper tip. For this reason, a wrench is often called a “tamper-proof” or “safety” bit.
The problem with wrench tips
As useful as snake eye wrench tips are for adding security to an assembly, they also have some disadvantages. The key tips are made to fit a very specific drive size. If they are used with the wrong size, it is increasingly likely that the tip will break.
Key bits are also more likely to break than any other type of bit. The tip of the wrench has two prongs that fit into two holes in the screw head. Pressure is then applied directly to only the two ends (in a very small area) that turn the screw. Other drills can have up to six sides that push against the head, making them less likely to break by distributing the load across multiple contact points.
Key tips are commonly avoided for this reason, but there are actually some simple steps you can take to avoid most of the common reasons for key breakage.
Steps to Avoid Breaking Important Tips
Always pre-drill hardwood
Hardwood can be especially difficult to cut through screws. It is recommended to pre-drill a pilot hole even when the screw has a self-drilling tip. Pre-drilling a hole removes much of the wood that would otherwise be in the way and allows for a screw to be installed more easily.
Avoid stopping suddenly
Knotting or using a screw that is too long where it can hit the metal on the back of the installation surface can cause the screw to stick in place. This sudden attack will put all the pressure on the tip tips and will likely cause them to break.
Avoid over-installation (excessive torque) of the screw
When installing the screw, be sure to stop when the head hits the installation material. Attempting to tighten the fastener further will significantly increase the amount of torque needed to turn the screw.
