Self Tapping Vs. Self Drilling Screws
What Are Self Tapping Screws?
Unless you are planning on through bolting something (the process of sliding a bolt through a hole and connecting a nut to the other side to hold it in place), almost every situation involving a bolt requires a tapped hole. A tap is a tool that can be inserted into a hole after it has been drilled and creates threading for the screw to fasten into.
Self tapping screws eliminate the need for a tap by having sharp cutting threads that can tap the threading themselves while being fastened. There are two large benefits of using self tapping screws. The first is that they save time and money by eliminating the need for a tap. The second is that the resulting threading they create is much more precise and creates a tighter stronger connection. It is common to see self tapping screws used in steel and masonry materials but they can also cut into plastic or wood.
What Are Self Drilling Screws?
Self drilling screws are a commonly used variety of screw for quick drilling into both metal and wood. A self drilling screw can typically be identified by its point and flute (notch) tip. This tip acts as a drill bit for the screw making it much faster to install then having to switch between a drill bit and driver bit.
The notched area in the tip acts as a reservoir to receive wood chips or metal filings. This creates the space necessary to drill/screw the screw all the way into place.
Self Drilling Screws are almost always made out of hard steel or some metal that has been treated to increase its hardness (such as 410 stainless steel). Always make sure when using self drilling screws, the material you drill into is softer than the screw material itself. Otherwise, the screws drilling tip will dull and not cut into the material. All self drilling screws are also self tapping by the nature of how they work.
Self drilling screws are a time saver eliminating both the steps of drilling (in most cases) and tapping a hole prior to installation. This also eliminates the need for drill bits and taps and switching between them for each hole.
*While these screws are able to drill their own holes, we still recommend using a standard drill bit first especially when going through very thin wood. This step will limit the amount chance of splitting/cracking significantly.
Self Drilling Vs Self Tapping: Which Is Better?
In the world of fasteners, the usual answer for which is better comes down almost entirely to the situation the fastener is being used for. From a time saving point of view, a self drilling screw is the better choice because it can eliminate the need for a drill bit making installations a one step process. However, both have their place and it comes down to knowing which to use in the situation at hand.