![Self Drilling Screws Properties 1 Self Drilling Screws Properties](https://excel.civilmdc.com/wp-content/uploads/2021/12/Self-Drilling-Screws-Properties.png)
Self tapping screws tap their own thread, so they need a pilot hole slightly smaller than the screws diameter. The idea is, you drill a pilot hole into wood or another soft material. Then as you drive the tapping screw in, its threads will dig into the material keeping it secure.