Except it's all at once, rather than you having to drill the hole and then chisel it out. The chisel part of the bit pushes the wood towards the drill part of the bit as you drill, and then the drill part of the bit removes that wood, same as the wood the bit is actually drilling through
So they drill round and you chisel it square.
Except it's all at once, rather than you having to drill the hole and then chisel it out. The chisel part of the bit pushes the wood towards the drill part of the bit as you drill, and then the drill part of the bit removes that wood, same as the wood the bit is actually drilling through