I needed to attach two 2x4 as T-joint and was looking to buy self-drilling wood screws to do that. In HomeDepot, I found a box of screws labeled as 'self-cutting' and bought it. But, when I opened the box and looked at the tip of the screws, I found that they had gaps on the threads (like this one)
rather than having a drill bit. The threads are tapered on the tip but remained all the way upto the tip.
Can they self-drill? Or, do I need pre-drilling? In HomeDepot, I found that there were many self-drilling screws for metal sheet (for example, metal-to-metal or wood-to-metal) but coundn't find any for wood-to-wood attachment. Can I use those metal sheet self-drilling screws for wood-to-wood connection?