If you are looking for self-tapping screws that will drill their own hole and then tap threads into steel, there is couple of things to consider. Self-tapping screws are available that can drill and tap standard steel like maybe 12 gauge steel relatively easily.  These have what is called a #3 point.  There also self-tapping screws that can drill and tap into steel up to ½” thick!  These screws have what is called a #5 point.  See the videos below, it’s pretty cool.   Here are few things to consider with self-tapping screws.

This first thing to consider with self-tapping screws is how thick of steel are you going to fasten to.  Self-drill and tap screws have drill points ranging from #2-#5.  The most common is the #3 and #5.  A number 3 drill point is usually for steel ranging from .035” to .176”.  A number 5 point can drill steel ranging from .125” to .5”.  Put simply a number three point would be for steel under 3/16” and.  After that you will need to jump up to a #4 or #5 point.  Check out the chart for a list of how thick of steel each drill point can handle.

Once you have decided on what drill point you need, consider the length you need.  This may seem like a pretty simple thing to mention but you want to keep in mind that the first part of a self-tapping screw is a drill point so it has no thread on it.  This is especially pronounced with the number 5 point self-tappers as the drill point is around ¾” long so make certain to compensate for that.  In addition to the length choose your diameter and head style.  If you are fastening 2x material to thick steel, consider a self-tapping screw that is a flat head and has wings to aid in the install.  You can read more about that screw here.  Also consider if you screw will need an exterior coating either for outdoor use or use in treated lumber.

For installing self-tapping screws, I prefer an impact driver.  They spin faster and can help set the screws faster.  Make certain you have the right size socket or phillips tip.  Setting self-tapping screws will take a little bit of pressure, you will need to get behind the driver and push so again it really helps to have the right bit tip or socket.

This post really just provides a basic overview of self-tapping screws.  There are stainless steel self-drillers, some with seal washers, low profile heads, counter sunk flat heads and more.  Hopefully this post shows you how handy these screws are.  Make sure you have them on hand for your next project!